TEM Studies of Segregation in a Ge-Sb-Te Alloy during Heating.
Abstract not provided.
Singh, Manish Kumar-X↗
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Effects of carbon concentration on the local atomic structure of amorphous GST
Ge-Sb-Te (GST) alloys are leading phase-change materials for data storage due to the fast phase transition between amorphous and crystalline states. Ongoing research aims at improving the stability of the amorphous phase to improve retention. This can be accomplished by the introduction of carbon as a dopant to Ge 2 Sb 2 Te 5 , which is known to alter the short- and mid-range structure of the amorphous phase and form covalently bonded C clusters, both of which hinder crystallization. The relative importance of these processes as a function of C concentration is not known. Here we used molecular dynamics simulation based on density functional theory to study how carbon doping affects the atomic structure of GST-C. Carbon doping results in an increase in tetrahedral coordination, especially of Ge atoms, and this is known to stabilize the amorphous phase. We observe an unexpected, non-monotonous trend in the number of tetrahedral bonded Ge with the amount of carbon doping. Our simulations show an increase in the number of tetrahedral bonded Ge up to 5 at.% C, after which the number saturates and begins to decrease above 14 at.% C. The carbon atoms aggregate into clusters, mostly in the form of chains and graphene flakes, leaving less carbon to disrupt the GST matrix at higher carbon concentrations. Different degrees of carbon clustering can explain divergent experimental results for recrystallization temperature for carbon doped GST.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Phase evolution and amorphous stability upon solid-state reaction in superlattice like Ge–Sb–Te combinatorial thin-film
In this paper, the superlattice-like (SLL) Ge–Sb–Te combinatorial thin films were prepared by using a high-throughput ion beam sputtering system. The phase evolution and amorphous stability of such films undergoing heat treatment as a function of the coating sequence and modulation period were systematically studied. The composition structure diagram was constructed via an automated process of data obtained by high-throughput synchrotron micro-X-ray diffraction and lab-based micro-X-ray fluorescence. Furthermore, the element distribution and microstructure in the depth direction of the SLL thin films were characterized with time-of-flight secondary ion mass spectrometry and transmission electron microscopy, respectively. These studies demonstrated that the coating sequence has a significant effect on the element distribution in the as-deposited SLL thin films and the structure of the final product upon solid-state reaction. Reducing the modulation period of the SLL thin film improves the stability of the amorphous Ge–Sb–Te phase. This work lays a solid foundation for the rational design of SLL Ge–Sb–Te thin films to improve their performance.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Materials Data on GeSb4Te7 by Materials Project
Ge1Sb4Te7 is MAX Phase-like structured and crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Ge(SbTe2)2 sheet oriented in the (0, 0, 1) direction and one Sb2Te3 sheet oriented in the (0, 0, 1) direction. In the Ge(SbTe2)2 sheet, Ge4+ is bonded to six equivalent Te2- atoms to form GeTe6 octahedra that share corners with six equivalent SbTe6 octahedra, edges with six equivalent GeTe6 octahedra, and edges with six equivalent SbTe6 octahedra. The corner-sharing octahedral tilt angles are 5°. All Ge–Te bond lengths are 3.02 Å. Sb+2.50+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent GeTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with six equivalent SbTe6 octahedra. The corner-sharing octahedral tilt angles are 5°. There are three shorter (3.02 Å) and three longer (3.21 Å) Sb–Te bond lengths. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Sb+2.50+ atoms to form a mixture of corner and edge-sharing TeGe3Sb3 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Sb+2.50+ atoms. In the Sb2Te3 sheet, Sb+2.50+ is bonded to six Te2- atoms to form a mixture of corner and edge-sharing SbTe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (3.03 Å) and three longer (3.19 Å) Sb–Te bond lengths. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to six equivalent Sb+2.50+ atoms to form edge-sharing TeSb6 octahedra. In the second Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Sb+2.50+ atoms.
36 MATERIALS SCIENCE↗
Materials Data on Ge2Sb2Te5 by Materials Project
Ge2Sb2Te5 is MAX Phase-like structured and crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Ge2Sb2Te5 sheet oriented in the (0, 0, 1) direction. Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with three equivalent SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with six equivalent GeTe6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are three shorter (2.84 Å) and three longer (3.30 Å) Ge–Te bond lengths. Sb1+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent SbTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with nine equivalent SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are three shorter (3.02 Å) and three longer (3.19 Å) Sb–Te bond lengths. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to six equivalent Sb1+ atoms to form TeSb6 octahedra that share corners with six equivalent TeGe3Sb3 octahedra and edges with twelve TeSb6 octahedra. The corner-sharing octahedral tilt angles are 4°. In the second Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Sb1+ atoms to form a mixture of edge and corner-sharing TeGe3Sb3 octahedra. The corner-sharing octahedral tilt angles are 4°. In the third Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Ge4+ atoms.
36 MATERIALS SCIENCE↗
Materials Data on Ge9(Sb5Te12)2 by Materials Project
Ge9(Sb5Te12)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are nine inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to six Te2- atoms to form distorted GeTe6 octahedra that share corners with five GeTe6 octahedra, edges with two equivalent GeTe6 octahedra, and edges with six SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 10–14°. There are a spread of Ge–Te bond distances ranging from 2.80–3.42 Å. In the second Ge4+ site, Ge4+ is bonded in a 6-coordinate geometry to six Te2- atoms. There are a spread of Ge–Te bond distances ranging from 2.74–3.46 Å. In the third Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with four equivalent GeTe6 octahedra, edges with six SbTe6 octahedra, and edges with four equivalent GeTe5 square pyramids. The corner-sharing octahedra tilt angles range from 6–7°. There are a spread of Ge–Te bond distances ranging from 2.88–3.33 Å. In the fourth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with five GeTe6 octahedra, edges with four equivalent GeTe6 octahedra, and edges with eight SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 9–10°. There are a spread of Ge–Te bond distances ranging from 2.85–3.31 Å. In the fifth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form distorted GeTe6 octahedra that share a cornercorner with one SbTe6 octahedra, corners with four equivalent GeTe6 octahedra, edges with two equivalent GeTe6 octahedra, and edges with four equivalent SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 2–12°. There are a spread of Ge–Te bond distances ranging from 2.68–3.38 Å. In the sixth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form distorted GeTe6 octahedra that share corners with five GeTe6 octahedra and edges with eight SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 5–12°. There are a spread of Ge–Te bond distances ranging from 2.78–3.42 Å. In the seventh Ge4+ site, Ge4+ is bonded to five Te2- atoms to form distorted GeTe5 square pyramids that share corners with four SbTe6 octahedra, corners with four equivalent GeTe5 square pyramids, edges with two equivalent SbTe6 octahedra, and edges with four equivalent GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 82–84°. There are a spread of Ge–Te bond distances ranging from 2.65–3.24 Å. In the eighth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form distorted GeTe6 octahedra that share corners with six GeTe6 octahedra and edges with eight SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 4–12°. There are a spread of Ge–Te bond distances ranging from 2.77–3.43 Å. In the ninth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with five GeTe6 octahedra, edges with four equivalent GeTe6 octahedra, and edges with eight SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 7–9°. There are a spread of Ge–Te bond distances ranging from 2.85–3.36 Å. There are ten inequivalent Sb+1.20+ sites. In the first Sb+1.20+ site, Sb+1.20+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with five SbTe6 octahedra, corners with two equivalent GeTe5 square pyramids, edges with four GeTe6 octahedra, and edges with four equivalent SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 6–11°. There are a spread of Sb–Te bond distances ranging from 2.87–3.29 Å. In the second Sb+1.20+ site, Sb+1.20+ is bonded to six Te2- atoms to form distorted SbTe6 octahedra that share corners with six SbTe6 octahedra, edges with four GeTe6 octahedra, and edges with four equivalent SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 6–19°. There are a spread of Sb–Te bond distances ranging from 2.81–3.40 Å. In the third Sb+1.20+ site, Sb+1.20+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with six SbTe6 octahedra, edges with four equivalent SbTe6 octahedra, and edges with six GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 4–16°. There are a spread of Sb–Te bond distances ranging from 2.82–3.37 Å. In the fourth Sb+1.20+ site, Sb+1.20+ is bonded to six Te2- atoms to form distorted SbTe6 octahedra that share a cornercorner with one GeTe6 octahedra, corners with five SbTe6 octahedra, edges with four equivalent SbTe6 octahedra, and edges with six GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 2–15°. There are a spread of Sb–Te bond distances ranging from 2.79–3.45 Å. In the fifth Sb+1.20+ site, Sb+1.20+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with six SbTe6 octahedra and edges with six GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 7–12°. There are a spread of Sb–Te bond distances ranging from 2.86–3.34 Å. In the sixth Sb+1.20+ site, Sb+1.20+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with six SbTe6 octahedra, corners with two equivalent GeTe5 square pyramids, edges with four GeTe6 octahedra, and edges with four equivalent SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 6–10°. There are a spread of Sb–Te bond distances ranging from 2.93–3.19 Å. In the seventh Sb+1.20+ site, Sb+1.20+ is bonded to six Te2- atoms to form distorted SbTe6 octahedra that share corners with six SbTe6 octahedra, edges with two equivalent GeTe6 octahedra, and edges with two equivalent GeTe5 square pyramids. The corner-sharing octahedra tilt angles range from 10–19°. There are a spread of Sb–Te bond distances ranging from 2.82–3.44 Å. In the eighth Sb+1.20+ site, Sb+1.20+ is bonded to six Te2- atoms to form distorted SbTe6 octahedra that share corners with six SbTe6 octahedra, edges with four GeTe6 octahedra, and edges with four equivalent SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 8–19°. There are a spread of Sb–Te bond distances ranging from 2.83–3.38 Å. In the ninth Sb+1.20+ site, Sb+1.20+ is bonded to six Te2- atoms to form distorted SbTe6 octahedra that share corners with six SbTe6 octahedra, edges with four equivalent SbTe6 octahedra, and edges with six GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 4–18°. There are a spread of Sb–Te bond distances ranging from 2.78–3.52 Å. In the tenth Sb+1.20+ site, Sb+1.20+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with six SbTe6 octahedra, edges with four equivalent SbTe6 octahedra, and edges with six GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Sb–Te bond distances ranging from 3.03–3.15 Å. There are twenty-four inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to one Ge4+ and four Sb+1.20+ atoms to form TeGeSb4 square pyramids that share a cornercorner with one TeGe2Sb4 octahedra, corners with four equivalent TeGeSb4 square pyramids, and edges with eight TeGe4Sb2 octahedra. The corner-sharing octahedral tilt angles are 7°. In the second Te2- site, Te2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ge4+ and two equivalent Sb+1.20+ atoms. In the third Te2- site, Te2- is bonded in a distorted T-shaped geometry to one Ge4+ and two equivalent Sb+1.20+ atoms. In the fourth Te2- site, Te2- is bonded to two Ge4+ and four Sb+1.20+ atoms to form TeGe2Sb4 octahedra that share corners with five TeGe2Sb4 octahedra and a cornercorner with one TeGeSb4 square pyramid. The corner-sharing octahedra tilt angles range from 11–15°. In the fifth Te2- site, Te2- is bonded to two Ge4+ and four Sb+1.20+ atoms to form TeGe2Sb4 octahedra that share corners with five TeGe4Sb2 octahedra, a cornercorner with one TeGeSb4 square pyramid, edges with four TeGe4Sb2 octahedra, and edges with four equivalent TeGeSb4 square pyramids. The corner-sharing octahedra tilt angles range from 2–12°. In the sixth Te2- site, Te2- is bonded to four Ge4+ and two equivalent Sb+1.20+ atoms to form corner-sharing TeGe4Sb2 octahedra. The corner-sharing octahedra tilt angles range from 11–12°. In the seventh Te2- site, Te2- is bonded to one Ge4+ and four Sb+1.20+ atoms to form TeGeSb4 square pyramids that share corners with four equivalent TeGeSb4 square pyramids, edges with two equivalent TeGe4Sb2 octahedra, and edges with six TeGeSb4 square pyramids. In the eighth Te2- site, Te2- is bonded in a distorted rectangular see-saw-like geometry to two Ge4+ and two equivalent Sb+1.20+ atoms. In the ninth Te2- site, Te2- is bonded in a distorted square co-planar geometry to four Sb+1.20+ atoms. In the tenth Te2- site, Te2- is bonded to one Ge4+ and four Sb+1.20+ atoms to form distorted TeGeSb4 square pyramids that share a cornercorner with one TeGe2Sb4 octahedra, corners with four equivalent TeGeSb4 square pyramids, and edges with eight TeGe4Sb2 octahedra. The corner-sharing octahedral tilt angles are 9°. In the eleventh Te2- site, Te2- is bonded in a distorted L-shaped geometry to three Ge4+ atoms. In the twelfth Te2- site, Te2- is bonded in a distorted rectangular see-saw-like geometry to three Ge4+ and one Sb+1.20+ atom. In the thirteenth Te2- site, Te2- is bonded to four Ge4+ and one Sb+1.20+ atom to form TeGe4Sb square pyramids that share corners with six TeGeSb4 square pyramids, edges with four equivalent TeGe4Sb2 octahedra, and edges with two equivalent TeGeSb4 square pyramids. In the fourteenth Te2- site, Te2- is bonded in a 4-coordinate geometry to two equivalent Ge4+ and two Sb+1.20+ atoms. In the fifteenth Te2- site, Te2- is bonded in a 2-coordinate geometry to two equivalent Ge4+ and two Sb+1.20+ atoms. In the sixteenth Te2- site, Te2- is bonded to four Ge4+ and two Sb+1.20+ atoms to form distorted TeGe4Sb2 octahedra that share corners with four equivalent TeGe4Sb2 octahedra, edges with eight TeGe4Sb2 octahedra, and edges with four TeGeSb4 square pyramids. The corner-sharing octahedra tilt angles range from 7–9°. In the seventeenth Te2- site, Te2- is bonded in a 4-coordinate geometry to two equivalent Ge4+ and two Sb+1.20+ atoms. In the eighteenth Te2- site, Te2- is bonded in a 3-coordinate geometry to two equivalent Ge4+ and two Sb+1.20+ atoms. In the nineteenth Te2- site, Te2- is bonded to four Ge4+ and two Sb+1.20+ atoms to form distorted TeGe4Sb2 octahedra that share corners with four equivalent TeGe4Sb2 octahedra, corners with two equivalent TeGeSb4 square pyramids, and edges with six TeGeSb4 square pyramids. The corner-sharing octahedra tilt angles range from 6–16°. In the twentieth Te2- site, Te2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ge4+ and two Sb+1.20+ atoms. In the twenty-first Te2- site, Te2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ge4+ and two Sb+1.20+ atoms. In the twenty-second Te2- site, Te2- is bonded to four Ge4+ and two Sb+1.20+ atoms to form distorted TeGe4Sb2 octahedra that share corners with four equivalent TeGe4Sb2 octahedra, edges with eight TeGe4Sb2 octahedra, and edges with four TeGeSb4 square pyramids. The corner-sharing octahedra tilt angles range from 8–9°. In the twenty-third Te2- site, Te2- is bonded to one Ge4+ and four Sb+1.20+ atoms to form distorted TeGeSb4 square pyramids that share corners with three TeGe4Sb2 octahedra, corners with six TeGeSb4 square pyramids, and edges with four equivalent TeGeSb4 square pyramids. The corner-sharing octahedra tilt angles range from 10–87°. In the twenty-fourth Te2- site, Te2- is bonded to two Ge4+ and four Sb+1.20+ atoms to form TeGe2Sb4 octahedra that share corners with five TeGe2Sb4 octahedra, a cornercorner with one TeGeSb4 square pyramid, edges with four TeGe4Sb2 octahedra, and edges with four equivalent TeGeSb4 square pyramids. The corner-sharing octahedra tilt angles range from 10–13°.
36 MATERIALS SCIENCE↗
Materials Data on Ge(SbTe2)2 by Materials Project
Ge(SbTe2)2 crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with two equivalent SbTe6 octahedra, corners with four equivalent GeTe6 octahedra, and edges with eight SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are two shorter (3.00 Å) and four longer (3.06 Å) Ge–Te bond lengths. There are two inequivalent Sb2+ sites. In the first Sb2+ site, Sb2+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with four equivalent SbTe6 octahedra, edges with four equivalent GeTe6 octahedra, and edges with four equivalent SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are two shorter (3.05 Å) and four longer (3.06 Å) Sb–Te bond lengths. In the second Sb2+ site, Sb2+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with four equivalent SbTe6 octahedra, edges with four equivalent GeTe6 octahedra, and edges with four equivalent SbTe6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are two shorter (3.05 Å) and four longer (3.06 Å) Sb–Te bond lengths. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to two equivalent Ge4+ and three Sb2+ atoms to form a mixture of edge and corner-sharing TeGe2Sb3 square pyramids. In the second Te2- site, Te2- is bonded in a square co-planar geometry to one Ge4+ and three Sb2+ atoms.
36 MATERIALS SCIENCE↗
Materials Data on Ge3(SbTe3)2 by Materials Project
Ge3Sb2Te6 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with four equivalent GeTe6 octahedra, edges with five GeTe6 octahedra, and edges with five equivalent SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are a spread of Ge–Te bond distances ranging from 2.92–3.09 Å. In the second Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with four equivalent SbTe6 octahedra, edges with four equivalent SbTe6 octahedra, and edges with six equivalent GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of Ge–Te bond distances ranging from 2.97–3.05 Å. Sb is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with four equivalent SbTe6 octahedra, edges with two equivalent SbTe6 octahedra, and edges with seven GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Sb–Te bond distances ranging from 3.01–3.09 Å. There are four inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to four Ge4+ and one Sb atom to form TeGe4Sb square pyramids that share corners with five TeGe4Sb square pyramids, edges with three equivalent TeGe4Sb2 octahedra, and edges with five TeGe4Sb square pyramids. In the second Te2- site, Te2- is bonded to four Ge4+ and two equivalent Sb atoms to form TeGe4Sb2 octahedra that share corners with two equivalent TeGe4Sb2 octahedra, corners with four equivalent TeGe2Sb3 square pyramids, and edges with ten TeGe4Sb square pyramids. The corner-sharing octahedral tilt angles are 0°. In the third Te2- site, Te2- is bonded to two Ge4+ and three equivalent Sb atoms to form TeGe2Sb3 square pyramids that share corners with two equivalent TeGe4Sb2 octahedra, corners with five TeGe4Sb square pyramids, edges with two equivalent TeGe4Sb2 octahedra, and edges with five TeGe4Sb square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. In the fourth Te2- site, Te2- is bonded in a square co-planar geometry to two equivalent Ge4+ and two equivalent Sb atoms.
36 MATERIALS SCIENCE↗
Materials Data on Ge2Sb2Te5 by Materials Project
Ge2Sb2Te5 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with two SbTe6 octahedra, corners with three GeTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with six SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Ge–Te bond distances ranging from 2.85–3.20 Å. In the second Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with two SbTe6 octahedra, corners with three GeTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with six SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. There are a spread of Ge–Te bond distances ranging from 2.82–3.19 Å. There are two inequivalent Sb1+ sites. In the first Sb1+ site, Sb1+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two GeTe6 octahedra, corners with three SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with six GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are a spread of Sb–Te bond distances ranging from 2.98–3.20 Å. In the second Sb1+ site, Sb1+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two GeTe6 octahedra, corners with three SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with six GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Sb–Te bond distances ranging from 2.95–3.19 Å. There are five inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to two Ge4+ and three Sb1+ atoms to form TeGe2Sb3 square pyramids that share corners with six TeGe2Sb3 square pyramids and edges with seven TeGe3Sb2 square pyramids. In the second Te2- site, Te2- is bonded in a rectangular see-saw-like geometry to two Ge4+ and two Sb1+ atoms. In the third Te2- site, Te2- is bonded to three Ge4+ and two Sb1+ atoms to form TeGe3Sb2 square pyramids that share corners with six TeGe3Sb2 square pyramids and edges with seven TeGe2Sb3 square pyramids. In the fourth Te2- site, Te2- is bonded to three Ge4+ and two Sb1+ atoms to form a mixture of corner and edge-sharing TeGe3Sb2 square pyramids. In the fifth Te2- site, Te2- is bonded to two Ge4+ and three Sb1+ atoms to form a mixture of corner and edge-sharing TeGe2Sb3 square pyramids.
36 MATERIALS SCIENCE↗
Materials Data on Ge(SbTe2)2 by Materials Project
Ge(SbTe2)2 is Calaverite-derived structured and crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three Ge(SbTe2)2 sheets oriented in the (0, 0, 1) direction. Ge4+ is bonded to six equivalent Te2- atoms to form GeTe6 octahedra that share corners with six equivalent TeSb3Te3 octahedra, edges with six equivalent GeTe6 octahedra, and edges with six equivalent TeSb3Te3 octahedra. The corner-sharing octahedral tilt angles are 7°. All Ge–Te bond lengths are 3.01 Å. Sb2+ is bonded in a distorted T-shaped geometry to three equivalent Te2- atoms. All Sb–Te bond lengths are 3.03 Å. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to three equivalent Sb2+ and three equivalent Te2- atoms to form TeSb3Te3 octahedra that share corners with three equivalent GeTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with six equivalent TeSb3Te3 octahedra. The corner-sharing octahedral tilt angles are 7°. All Te–Te bond lengths are 3.31 Å. In the second Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Te2- atoms to form a mixture of distorted corner and edge-sharing TeGe3Te3 octahedra. The corner-sharing octahedral tilt angles are 0°.
36 MATERIALS SCIENCE↗
Materials Data on Ge(SbTe2)2 by Materials Project
Ge(SbTe2)2 is MAX Phase-like structured and crystallizes in the trigonal R3m space group. The structure is two-dimensional and consists of three Ge(SbTe2)2 sheets oriented in the (0, 0, 1) direction. Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with three equivalent SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with six equivalent GeTe6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are three shorter (2.85 Å) and three longer (3.27 Å) Ge–Te bond lengths. There are two inequivalent Sb2+ sites. In the first Sb2+ site, Sb2+ is bonded to six Te2- atoms to form a mixture of edge and corner-sharing SbTe6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three shorter (3.01 Å) and three longer (3.20 Å) Sb–Te bond lengths. In the second Sb2+ site, Sb2+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent SbTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with nine SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 1–6°. There are three shorter (3.03 Å) and three longer (3.17 Å) Sb–Te bond lengths. There are four inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Sb2+ atoms. In the second Te2- site, Te2- is bonded to six Sb2+ atoms to form TeSb6 octahedra that share corners with three equivalent TeGe3Sb3 octahedra and edges with nine TeSb6 octahedra. The corner-sharing octahedral tilt angles are 4°. In the third Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Sb2+ atoms to form a mixture of edge and corner-sharing TeGe3Sb3 octahedra. The corner-sharing octahedral tilt angles are 4°. In the fourth Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Ge4+ atoms.
36 MATERIALS SCIENCE↗
Materials Data on Ge3(SbTe3)2 by Materials Project
Ge3Sb2Te6 is MAX Phase-like structured and crystallizes in the trigonal R3m space group. The structure is two-dimensional and consists of three Ge3Sb2Te6 sheets oriented in the (0, 0, 1) direction. there are three inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with nine GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 6–14°. There are three shorter (2.84 Å) and three longer (3.29 Å) Ge–Te bond lengths. In the second Ge4+ site, Ge4+ is bonded to six Te2- atoms to form a mixture of distorted edge and corner-sharing GeTe6 octahedra. The corner-sharing octahedral tilt angles are 14°. There are three shorter (2.84 Å) and three longer (3.40 Å) Ge–Te bond lengths. In the third Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with three equivalent SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with six equivalent GeTe6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are three shorter (2.84 Å) and three longer (3.29 Å) Ge–Te bond lengths. There are two inequivalent Sb sites. In the first Sb site, Sb is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent SbTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with nine SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are three shorter (3.01 Å) and three longer (3.21 Å) Sb–Te bond lengths. In the second Sb site, Sb is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent SbTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with nine SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are three shorter (3.02 Å) and three longer (3.18 Å) Sb–Te bond lengths. There are six inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to six Sb atoms to form a mixture of edge and corner-sharing TeSb6 octahedra. The corner-sharing octahedra tilt angles range from 4–5°. In the second Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Sb atoms to form TeGe3Sb3 octahedra that share corners with three equivalent TeSb6 octahedra and edges with nine TeGe3Sb3 octahedra. The corner-sharing octahedral tilt angles are 5°. In the third Te2- site, Te2- is bonded to six Ge4+ atoms to form distorted TeGe6 octahedra that share corners with three equivalent TeGe3Sb3 octahedra and edges with nine TeGe6 octahedra. The corner-sharing octahedral tilt angles are 12°. In the fourth Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Ge4+ atoms. In the fifth Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Sb atoms to form a mixture of edge and corner-sharing TeGe3Sb3 octahedra. The corner-sharing octahedra tilt angles range from 4–12°. In the sixth Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Ge4+ atoms.
36 MATERIALS SCIENCE↗
Materials Data on Ge13Sb13Te32 by Materials Project
Ge13Sb13Te32 is Orthorhombic Perovskite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are thirteen inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded in a 5-coordinate geometry to six Te2- atoms. There are a spread of Ge–Te bond distances ranging from 2.77–3.50 Å. In the second Ge4+ site, Ge4+ is bonded to six Te2- atoms to form distorted GeTe6 octahedra that share corners with two equivalent GeTe6 octahedra, edges with four GeTe6 octahedra, and edges with four SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 14–17°. There are a spread of Ge–Te bond distances ranging from 2.77–3.32 Å. In the third Ge4+ site, Ge4+ is bonded to five Te2- atoms to form distorted GeTe5 square pyramids that share a cornercorner with one GeTe6 octahedra, corners with four SbTe6 octahedra, an edgeedge with one GeTe6 octahedra, and edges with five SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 14–81°. There are a spread of Ge–Te bond distances ranging from 2.75–3.25 Å. In the fourth Ge4+ site, Ge4+ is bonded in a 5-coordinate geometry to five Te2- atoms. There are a spread of Ge–Te bond distances ranging from 2.74–3.29 Å. In the fifth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with two equivalent GeTe6 octahedra, a cornercorner with one GeTe5 square pyramid, edges with three GeTe6 octahedra, and edges with five SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 5–7°. There are a spread of Ge–Te bond distances ranging from 2.83–3.32 Å. In the sixth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with two equivalent SbTe6 octahedra, corners with four GeTe6 octahedra, edges with two SbTe6 octahedra, edges with four GeTe6 octahedra, and an edgeedge with one GeTe5 square pyramid. The corner-sharing octahedra tilt angles range from 5–12°. There are a spread of Ge–Te bond distances ranging from 2.78–3.33 Å. In the seventh Ge4+ site, Ge4+ is bonded to six Te2- atoms to form distorted GeTe6 octahedra that share corners with six SbTe6 octahedra, edges with three GeTe6 octahedra, edges with three SbTe6 octahedra, and edges with two GeTe5 square pyramids. The corner-sharing octahedra tilt angles range from 3–15°. There are a spread of Ge–Te bond distances ranging from 2.73–3.42 Å. In the eighth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form distorted GeTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with two equivalent SbTe6 octahedra, a cornercorner with one GeTe5 square pyramid, edges with three SbTe6 octahedra, and edges with five GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 11–17°. There are a spread of Ge–Te bond distances ranging from 2.77–3.36 Å. In the ninth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share edges with four GeTe6 octahedra, edges with seven SbTe6 octahedra, and an edgeedge with one GeTe5 square pyramid. There are a spread of Ge–Te bond distances ranging from 2.93–3.12 Å. In the tenth Ge4+ site, Ge4+ is bonded to five Te2- atoms to form distorted GeTe5 square pyramids that share corners with two GeTe6 octahedra, corners with three SbTe6 octahedra, edges with three SbTe6 octahedra, and edges with four GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 7–82°. There are a spread of Ge–Te bond distances ranging from 2.71–3.31 Å. In the eleventh Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with two equivalent SbTe6 octahedra, a cornercorner with one GeTe5 square pyramid, an edgeedge with one GeTe6 octahedra, and edges with eight SbTe6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are a spread of Ge–Te bond distances ranging from 2.89–3.25 Å. In the twelfth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with four SbTe6 octahedra, edges with four GeTe6 octahedra, and edges with four SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 5–15°. There are a spread of Ge–Te bond distances ranging from 2.82–3.24 Å. In the thirteenth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with two equivalent SbTe6 octahedra, edges with three SbTe6 octahedra, edges with four GeTe6 octahedra, and an edgeedge with one GeTe5 square pyramid. The corner-sharing octahedra tilt angles range from 8–12°. There are a spread of Ge–Te bond distances ranging from 2.82–3.34 Å. There are thirteen inequivalent Sb+0.92+ sites. In the first Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with four SbTe6 octahedra, a cornercorner with one GeTe5 square pyramid, edges with two SbTe6 octahedra, and edges with four GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 1–9°. There are a spread of Sb–Te bond distances ranging from 2.95–3.19 Å. In the second Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent SbTe6 octahedra, a cornercorner with one GeTe5 square pyramid, edges with three SbTe6 octahedra, and edges with four GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. There are a spread of Sb–Te bond distances ranging from 3.02–3.14 Å. In the third Sb+0.92+ site, Sb+0.92+ is bonded in a 6-coordinate geometry to six Te2- atoms. There are a spread of Sb–Te bond distances ranging from 2.79–3.57 Å. In the fourth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with two equivalent SbTe6 octahedra, edges with three SbTe6 octahedra, and edges with five GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 3–15°. There are a spread of Sb–Te bond distances ranging from 2.90–3.38 Å. In the fifth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form distorted SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with two equivalent SbTe6 octahedra, edges with two GeTe6 octahedra, edges with four SbTe6 octahedra, and an edgeedge with one GeTe5 square pyramid. The corner-sharing octahedra tilt angles range from 7–24°. There are a spread of Sb–Te bond distances ranging from 2.82–3.52 Å. In the sixth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with two equivalent SbTe6 octahedra, edges with two GeTe6 octahedra, edges with four SbTe6 octahedra, and edges with two GeTe5 square pyramids. The corner-sharing octahedra tilt angles range from 10–16°. There are a spread of Sb–Te bond distances ranging from 2.88–3.35 Å. In the seventh Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent SbTe6 octahedra, a cornercorner with one GeTe5 square pyramid, edges with four GeTe6 octahedra, and edges with four SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 8–9°. There are a spread of Sb–Te bond distances ranging from 2.92–3.30 Å. In the eighth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form distorted SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with two equivalent SbTe6 octahedra, edges with three GeTe6 octahedra, and edges with five SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 11–14°. There are a spread of Sb–Te bond distances ranging from 2.84–3.55 Å. In the ninth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent SbTe6 octahedra, corners with four GeTe5 square pyramids, edges with three GeTe6 octahedra, and edges with six SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 12–13°. There are a spread of Sb–Te bond distances ranging from 2.86–3.41 Å. In the tenth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with four SbTe6 octahedra, edges with three SbTe6 octahedra, and edges with five GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 2–15°. There are a spread of Sb–Te bond distances ranging from 2.82–3.39 Å. In the eleventh Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent SbTe6 octahedra, corners with four GeTe6 octahedra, edges with two GeTe6 octahedra, edges with five SbTe6 octahedra, and an edgeedge with one GeTe5 square pyramid. The corner-sharing octahedra tilt angles range from 6–24°. There are a spread of Sb–Te bond distances ranging from 2.85–3.47 Å. In the twelfth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form distorted SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with four SbTe6 octahedra, edges with two GeTe6 octahedra, edges with four SbTe6 octahedra, and edges with two GeTe5 square pyramids. The corner-sharing octahedra tilt angles range from 5–16°. There are a spread of Sb–Te bond distances ranging from 2.86–3.51 Å. In the thirteenth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with four SbTe6 octahedra, edges with three GeTe6 octahedra, edges with three SbTe6 octahedra, and edges with two GeTe5 square pyramids. The corner-sharing octahedra tilt angles range from 2–15°. There are a spread of Sb–Te bond distances ranging from 2.84–3.38 Å. There are thirty-two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to three Ge4+ and two Sb+0.92+ atoms to form distorted TeGe3Sb2 square pyramids that share corners with two TeGe3Sb3 octahedra, corners with four TeGeSb4 square pyramids, an edgeedge with one TeGe3Sb3 octahedra, and edges with three TeGe2Sb3 square pyramids. The corner-sharing octahedral tilt angles are 87°. In the second Te2- site, Te2- is bonded in a 4-coordinate geometry to two Ge4+ and three Sb+0.92+ atoms. In the third Te2- site, Te2- is bonded in a distorted rectangular see-saw-like geometry to three Ge4+ and one Sb+0.92+ atom. In the fourth Te2- site, Te2- is bonded in a distorted rectangular see-saw-like geometry to two Ge4+ and three Sb+0.92+ atoms. In the fifth Te2- site, Te2- is bonded in a 4-coordinate geometry to two Ge4+ and two Sb+0.92+ atoms. In the sixth Te2- site, Te2- is bonded in a distorted rectangular see-saw-like geometry to three Ge4+ and one Sb+0.92+ atom. In the seventh Te2- site, Te2- is bonded to one Ge4+ and four Sb+0.92+ atoms to form distorted TeGeSb4 square pyramids that share corners with five TeGe2Sb3 square pyramids, edges with three TeGe3Sb3 octahedra, and edges with three TeGe2Sb3 square pyramids. In the eighth Te2- site, Te2- is bonded to two Ge4+ and three Sb+0.92+ atoms to form distorted TeGe2Sb3 square pyramids that share corners with six TeGeSb4 square pyramids, edges with three TeGe3Sb3 octahedra, and an edgeedge with one TeGe2Sb3 square pyramid. In the ninth Te2- site, Te2- is bonded to two Ge4+ and three Sb+0.92+ atoms to form distorted TeGe2Sb3 square pyramids that share corners with four TeGe2Sb3 square pyramids, edges with two TeGe3Sb3 octahedra, and edges with four TeGeSb4 square pyramids. In the tenth Te2- site, Te2- is bonded in a 4-coordinate geometry to two Ge4+ and two Sb+0.92+ atoms. In the eleventh Te2- site, Te2- is bonded to two Ge4+ and three Sb+0.92+ atoms to form TeGe2Sb3 square pyramids that share corners with four TeGe3Sb3 octahedra, corners with two TeGe2Sb3 square pyramids, and edges with three TeGe2Sb3 square pyramids. The corner-sharing octahedra tilt angles range from 12–14°. In the twelfth Te2- site, Te2- is bonded to four Ge4+ and one Sb+0.92+ atom to form distorted TeGe4Sb square pyramids that share
36 MATERIALS SCIENCE↗
Materials Data on Ge(SbTe2)2 by Materials Project
Ge(SbTe2)2 is MAX Phase-like structured and crystallizes in the trigonal R3m space group. The structure is two-dimensional and consists of three Ge(SbTe2)2 sheets oriented in the (0, 0, 1) direction. Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with three equivalent SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with six equivalent GeTe6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are three shorter (2.86 Å) and three longer (3.32 Å) Ge–Te bond lengths. There are two inequivalent Sb2+ sites. In the first Sb2+ site, Sb2+ is bonded to six Te2- atoms to form a mixture of edge and corner-sharing SbTe6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three shorter (3.02 Å) and three longer (3.21 Å) Sb–Te bond lengths. In the second Sb2+ site, Sb2+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent SbTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with nine SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 1–7°. There are three shorter (3.03 Å) and three longer (3.16 Å) Sb–Te bond lengths. There are four inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Ge4+ atoms. In the second Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Sb2+ atoms. In the third Te2- site, Te2- is bonded to six Sb2+ atoms to form TeSb6 octahedra that share corners with three equivalent TeGe3Sb3 octahedra and edges with nine TeSb6 octahedra. The corner-sharing octahedral tilt angles are 3°. In the fourth Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Sb2+ atoms to form a mixture of edge and corner-sharing TeGe3Sb3 octahedra. The corner-sharing octahedral tilt angles are 3°.
36 MATERIALS SCIENCE↗
Materials Data on Ge2Sb2Te5 by Materials Project
Ge2Sb2Te5 is Caswellsilverite-like structured and crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Ge2Sb2Te5 sheet oriented in the (0, 0, 1) direction. Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with nine equivalent GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are three shorter (3.00 Å) and three longer (3.04 Å) Ge–Te bond lengths. Sb1+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent GeTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with six equivalent SbTe6 octahedra. The corner-sharing octahedral tilt angles are 5°. There are three shorter (3.01 Å) and three longer (3.20 Å) Sb–Te bond lengths. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to six equivalent Ge4+ atoms to form TeGe6 octahedra that share corners with six equivalent TeGe3Sb3 octahedra and edges with twelve TeGe6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Sb1+ atoms to form a mixture of edge and corner-sharing TeGe3Sb3 octahedra. The corner-sharing octahedral tilt angles are 1°. In the third Te2- site, Te2- is bonded in a 6-coordinate geometry to three equivalent Sb1+ atoms.
36 MATERIALS SCIENCE↗
Materials Data on GeSbTe3 by Materials Project
GeSbTe3 is MAX Phase-like structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. Ge3+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with three equivalent SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with six equivalent GeTe6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three shorter (2.86 Å) and three longer (3.14 Å) Ge–Te bond lengths. Sb3+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent GeTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with six equivalent SbTe6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three shorter (3.04 Å) and three longer (3.12 Å) Sb–Te bond lengths. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to three equivalent Ge3+ and three equivalent Sb3+ atoms to form edge-sharing TeGe3Sb3 octahedra. In the second Te2- site, Te2- is bonded in a 6-coordinate geometry to three equivalent Sb3+ and three equivalent Te2- atoms. All Te–Te bond lengths are 3.55 Å. In the third Te2- site, Te2- is bonded in a 6-coordinate geometry to three equivalent Ge3+ and three equivalent Te2- atoms.
36 MATERIALS SCIENCE↗