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DOE OSTI2020

Materials Data on K5As4 by Materials Project

K5As4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are five inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six As+1.25- atoms. There are a spread of K–As bond distances ranging from 3.38–3.78 Å. In the second K1+ site, K1+ is bonded in a 5-coordinate geometry to five As+1.25- atoms. There are a spread of K–As bond distances ranging from 3.33–3.52 Å. In the third K1+ site, K1+ is bonded to six As+1.25- atoms to form edge-sharing KAs6 octahedra. There are a spread of K–As bond distances ranging from 3.29–3.50 Å. In the fourth K1+ site, K1+ is bonded in a 4-coordinate geometry to five As+1.25- atoms. There are a spread of K–As bond distances ranging from 3.34–3.53 Å. In the fifth K1+ site, K1+ is bonded in a 6-coordinate geometry to six As+1.25- atoms. There are a spread of K–As bond distances ranging from 3.39–3.78 Å. There are four inequivalent As+1.25- sites. In the first As+1.25- site, As+1.25- is bonded in a 9-coordinate geometry to seven K1+ and two As+1.25- atoms. There are one shorter (2.46 Å) and one longer (2.51 Å) As–As bond lengths. In the second As+1.25- site, As+1.25- is bonded in a 8-coordinate geometry to seven K1+ and one As+1.25- atom. The As–As bond length is 2.46 Å. In the third As+1.25- site, As+1.25- is bonded in a 8-coordinate geometry to seven K1+ and one As+1.25- atom. In the fourth As+1.25- site, As+1.25- is bonded in a 9-coordinate geometry to seven K1+ and two As+1.25- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3Nb by Materials Project

K3Nb is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded to four equivalent K and four equivalent Nb atoms to form distorted KK4Nb4 cuboctahedra that share corners with eight equivalent NbK12 cuboctahedra, corners with sixteen KK4Nb4 cuboctahedra, edges with four equivalent NbK12 cuboctahedra, edges with sixteen KK4Nb4 cuboctahedra, and faces with six equivalent KK4Nb4 cuboctahedra. All K–K bond lengths are 4.05 Å. All K–Nb bond lengths are 4.05 Å. In the second K site, K is bonded to eight equivalent K and four equivalent Nb atoms to form KK8Nb4 cuboctahedra that share corners with eight equivalent NbK12 cuboctahedra, corners with twenty KK4Nb4 cuboctahedra, edges with sixteen KK4Nb4 cuboctahedra, faces with four equivalent KK8Nb4 cuboctahedra, and faces with six equivalent NbK12 cuboctahedra. All K–Nb bond lengths are 4.19 Å. Nb is bonded to twelve K atoms to form NbK12 cuboctahedra that share corners with four equivalent NbK12 cuboctahedra, corners with twenty-four KK4Nb4 cuboctahedra, edges with eight equivalent KK4Nb4 cuboctahedra, edges with eight equivalent NbK12 cuboctahedra, faces with four equivalent NbK12 cuboctahedra, and faces with six equivalent KK8Nb4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3Ta by Materials Project

K3Ta is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded to four equivalent K and four equivalent Ta atoms to form distorted KK4Ta4 cuboctahedra that share corners with eight equivalent TaK12 cuboctahedra, corners with sixteen KK4Ta4 cuboctahedra, edges with four equivalent TaK12 cuboctahedra, edges with sixteen KK4Ta4 cuboctahedra, and faces with six equivalent KK4Ta4 cuboctahedra. All K–K bond lengths are 4.00 Å. All K–Ta bond lengths are 4.00 Å. In the second K site, K is bonded to eight equivalent K and four equivalent Ta atoms to form KK8Ta4 cuboctahedra that share corners with eight equivalent TaK12 cuboctahedra, corners with twenty KK4Ta4 cuboctahedra, edges with sixteen KK4Ta4 cuboctahedra, faces with four equivalent KK8Ta4 cuboctahedra, and faces with six equivalent TaK12 cuboctahedra. All K–Ta bond lengths are 4.11 Å. Ta is bonded to twelve K atoms to form TaK12 cuboctahedra that share corners with four equivalent TaK12 cuboctahedra, corners with twenty-four KK4Ta4 cuboctahedra, edges with eight equivalent KK4Ta4 cuboctahedra, edges with eight equivalent TaK12 cuboctahedra, faces with four equivalent TaK12 cuboctahedra, and faces with six equivalent KK8Ta4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3Mn by Materials Project

K3Mn is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded to four equivalent K and four equivalent Mn atoms to form distorted KK4Mn4 cuboctahedra that share corners with eight equivalent MnK12 cuboctahedra, corners with sixteen KK4Mn4 cuboctahedra, edges with four equivalent MnK12 cuboctahedra, edges with sixteen KK4Mn4 cuboctahedra, and faces with six equivalent KK4Mn4 cuboctahedra. All K–K bond lengths are 4.08 Å. All K–Mn bond lengths are 4.08 Å. In the second K site, K is bonded to eight equivalent K and four equivalent Mn atoms to form KK8Mn4 cuboctahedra that share corners with eight equivalent MnK12 cuboctahedra, corners with twenty KK4Mn4 cuboctahedra, edges with sixteen KK4Mn4 cuboctahedra, faces with four equivalent KK8Mn4 cuboctahedra, and faces with six equivalent MnK12 cuboctahedra. All K–Mn bond lengths are 4.20 Å. Mn is bonded to twelve K atoms to form MnK12 cuboctahedra that share corners with four equivalent MnK12 cuboctahedra, corners with twenty-four KK4Mn4 cuboctahedra, edges with eight equivalent KK4Mn4 cuboctahedra, edges with eight equivalent MnK12 cuboctahedra, faces with four equivalent MnK12 cuboctahedra, and faces with six equivalent KK8Mn4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K4SnO3 by Materials Project

K4SnO3 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. there are four inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of K–O bond distances ranging from 2.66–2.79 Å. In the second K1+ site, K1+ is bonded to five O2- atoms to form distorted KO5 square pyramids that share corners with three equivalent KO4 tetrahedra, edges with two equivalent KO5 square pyramids, and edges with two equivalent KO4 tetrahedra. There are a spread of K–O bond distances ranging from 2.73–2.97 Å. In the third K1+ site, K1+ is bonded to four O2- atoms to form distorted KO4 tetrahedra that share corners with three equivalent KO5 square pyramids, corners with two equivalent KO4 tetrahedra, and edges with two equivalent KO5 square pyramids. There are a spread of K–O bond distances ranging from 2.69–2.82 Å. In the fourth K1+ site, K1+ is bonded in a distorted trigonal planar geometry to three O2- atoms. There are a spread of K–O bond distances ranging from 2.73–2.89 Å. Sn2+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of Sn–O bond distances ranging from 2.08–2.10 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to five K1+ and one Sn2+ atom. In the second O2- site, O2- is bonded to five K1+ and one Sn2+ atom to form a mixture of distorted edge and corner-sharing OK5Sn octahedra. The corner-sharing octahedra tilt angles range from 18–72°. In the third O2- site, O2- is bonded to five K1+ and one Sn2+ atom to form a mixture of distorted edge and corner-sharing OK5Sn octahedra. The corner-sharing octahedra tilt angles range from 18–72°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KPb2 by Materials Project

KPb2 is Hexagonal Laves structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. K is bonded in a 12-coordinate geometry to twelve Pb atoms. There are nine shorter (3.96 Å) and three longer (4.00 Å) K–Pb bond lengths. There are two inequivalent Pb sites. In the first Pb site, Pb is bonded to six equivalent K and six equivalent Pb atoms to form a mixture of face, edge, and corner-sharing PbK6Pb6 cuboctahedra. All Pb–Pb bond lengths are 3.39 Å. In the second Pb site, Pb is bonded to six equivalent K and six Pb atoms to form a mixture of face, edge, and corner-sharing PbK6Pb6 cuboctahedra. There are two shorter (3.35 Å) and two longer (3.40 Å) Pb–Pb bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KNa2 by Materials Project

KNa2 is Hexagonal Laves structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. K is bonded in a 12-coordinate geometry to four equivalent K and twelve Na atoms. There are three shorter (4.56 Å) and one longer (4.58 Å) K–K bond lengths. There are nine shorter (4.37 Å) and three longer (4.38 Å) K–Na bond lengths. There are two inequivalent Na sites. In the first Na site, Na is bonded to six equivalent K and six equivalent Na atoms to form a mixture of corner, edge, and face-sharing NaK6Na6 cuboctahedra. All Na–Na bond lengths are 3.74 Å. In the second Na site, Na is bonded to six equivalent K and six Na atoms to form a mixture of corner, edge, and face-sharing NaK6Na6 cuboctahedra. There are two shorter (3.71 Å) and two longer (3.73 Å) Na–Na bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K6InP3 by Materials Project

K6InP3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are six inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 4-coordinate geometry to one K1+ and four P3- atoms. The K–K bond length is 3.43 Å. There are a spread of K–P bond distances ranging from 3.29–3.68 Å. In the second K1+ site, K1+ is bonded to four P3- atoms to form a mixture of distorted edge and corner-sharing KP4 tetrahedra. There are a spread of K–P bond distances ranging from 3.24–3.46 Å. In the third K1+ site, K1+ is bonded in a 6-coordinate geometry to two K1+ and four P3- atoms. The K–K bond length is 3.39 Å. There are a spread of K–P bond distances ranging from 3.33–3.67 Å. In the fourth K1+ site, K1+ is bonded in a 4-coordinate geometry to four P3- atoms. There are a spread of K–P bond distances ranging from 3.29–3.60 Å. In the fifth K1+ site, K1+ is bonded to four P3- atoms to form a mixture of distorted edge and corner-sharing KP4 tetrahedra. There are a spread of K–P bond distances ranging from 3.43–3.50 Å. In the sixth K1+ site, K1+ is bonded in a distorted trigonal planar geometry to one K1+ and three P3- atoms. There are a spread of K–P bond distances ranging from 3.35–3.47 Å. In3+ is bonded in a trigonal planar geometry to three P3- atoms. There are a spread of In–P bond distances ranging from 2.55–2.60 Å. There are three inequivalent P3- sites. In the first P3- site, P3- is bonded in a 9-coordinate geometry to eight K1+ and one In3+ atom. In the second P3- site, P3- is bonded in a 8-coordinate geometry to seven K1+ and one In3+ atom. In the third P3- site, P3- is bonded in a 9-coordinate geometry to eight K1+ and one In3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3Ti by Materials Project

K3Ti is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded to four equivalent K and four equivalent Ti atoms to form distorted KK4Ti4 cuboctahedra that share corners with eight equivalent TiK12 cuboctahedra, corners with sixteen KK4Ti4 cuboctahedra, edges with four equivalent TiK12 cuboctahedra, edges with sixteen KK4Ti4 cuboctahedra, and faces with six equivalent KK4Ti4 cuboctahedra. All K–K bond lengths are 4.16 Å. All K–Ti bond lengths are 4.16 Å. In the second K site, K is bonded to eight equivalent K and four equivalent Ti atoms to form distorted KK8Ti4 cuboctahedra that share corners with eight equivalent TiK12 cuboctahedra, corners with twenty KK4Ti4 cuboctahedra, edges with sixteen KK4Ti4 cuboctahedra, faces with four equivalent KK8Ti4 cuboctahedra, and faces with six equivalent TiK12 cuboctahedra. All K–Ti bond lengths are 4.23 Å. Ti is bonded to twelve K atoms to form TiK12 cuboctahedra that share corners with four equivalent TiK12 cuboctahedra, corners with twenty-four KK4Ti4 cuboctahedra, edges with eight equivalent KK4Ti4 cuboctahedra, edges with eight equivalent TiK12 cuboctahedra, faces with four equivalent TiK12 cuboctahedra, and faces with six equivalent KK8Ti4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3FeF3 by Materials Project

K3FeF3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent K sites. In the first K site, K is bonded in a 6-coordinate geometry to six F atoms. There are a spread of K–F bond distances ranging from 2.76–3.21 Å. In the second K site, K is bonded in a 5-coordinate geometry to five F atoms. There are a spread of K–F bond distances ranging from 2.68–3.15 Å. In the third K site, K is bonded in a T-shaped geometry to three F atoms. There are a spread of K–F bond distances ranging from 2.51–2.60 Å. In the fourth K site, K is bonded in a T-shaped geometry to three F atoms. There are a spread of K–F bond distances ranging from 2.52–2.62 Å. In the fifth K site, K is bonded in a 6-coordinate geometry to six F atoms. There are a spread of K–F bond distances ranging from 2.79–3.22 Å. In the sixth K site, K is bonded in a 5-coordinate geometry to five F atoms. There are a spread of K–F bond distances ranging from 2.80–3.12 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded in a T-shaped geometry to three F atoms. There are two shorter (2.13 Å) and one longer (2.14 Å) Fe–F bond lengths. In the second Fe site, Fe is bonded in a T-shaped geometry to three F atoms. There are two shorter (2.13 Å) and one longer (2.18 Å) Fe–F bond lengths. There are six inequivalent F sites. In the first F site, F is bonded in a 6-coordinate geometry to five K and one Fe atom. In the second F site, F is bonded to five K and one Fe atom to form a mixture of distorted edge and corner-sharing FK5Fe octahedra. The corner-sharing octahedra tilt angles range from 5–6°. In the third F site, F is bonded in a 5-coordinate geometry to four K and one Fe atom. In the fourth F site, F is bonded in a 6-coordinate geometry to five K and one Fe atom. In the fifth F site, F is bonded in a 5-coordinate geometry to four K and one Fe atom. In the sixth F site, F is bonded to five K and one Fe atom to form a mixture of distorted edge and corner-sharing FK5Fe octahedra. The corner-sharing octahedra tilt angles range from 6–15°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2HfO2F5 by Materials Project

K2HfO2F5 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded to one O and six F atoms to form distorted KOF6 pentagonal bipyramids that share corners with four equivalent HfO2F5 pentagonal bipyramids, an edgeedge with one KOF6 pentagonal bipyramid, and an edgeedge with one HfO2F5 pentagonal bipyramid. The K–O bond length is 2.97 Å. There are a spread of K–F bond distances ranging from 2.63–2.88 Å. In the second K site, K is bonded in a 7-coordinate geometry to two equivalent O and five F atoms. There are one shorter (2.84 Å) and one longer (3.14 Å) K–O bond lengths. There are a spread of K–F bond distances ranging from 2.68–2.80 Å. Hf is bonded to two equivalent O and five F atoms to form distorted HfO2F5 pentagonal bipyramids that share corners with four equivalent KOF6 pentagonal bipyramids, an edgeedge with one KOF6 pentagonal bipyramid, and an edgeedge with one HfO2F5 pentagonal bipyramid. There are one shorter (2.24 Å) and one longer (2.26 Å) Hf–O bond lengths. There are a spread of Hf–F bond distances ranging from 1.98–2.05 Å. There are two inequivalent O sites. In the first O site, O is bonded in a T-shaped geometry to three K atoms. In the second O site, O is bonded in a 3-coordinate geometry to two equivalent Hf and one O atom. The O–O bond length is 1.42 Å. There are five inequivalent F sites. In the first F site, F is bonded to three K and one Hf atom to form a mixture of distorted corner and edge-sharing FK3Hf tetrahedra. In the second F site, F is bonded in a distorted bent 150 degrees geometry to one K and one Hf atom. In the third F site, F is bonded in a 3-coordinate geometry to two K and one Hf atom. In the fourth F site, F is bonded to three K and one Hf atom to form a mixture of distorted corner and edge-sharing FK3Hf tetrahedra. In the fifth F site, F is bonded in a 3-coordinate geometry to two K and one Hf atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KC4N3 by Materials Project

K(CN)3C crystallizes in the triclinic P-1 space group. The structure is one-dimensional and consists of two methane molecules and one K(CN)3 ribbon oriented in the (1, 0, 0) direction. In the K(CN)3 ribbon, K1+ is bonded to seven N3- atoms to form a mixture of distorted face and edge-sharing KN7 pentagonal bipyramids. There are a spread of K–N bond distances ranging from 2.88–3.09 Å. There are three inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. In the second C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. In the third C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted single-bond geometry to three equivalent K1+ and one C2+ atom. In the second N3- site, N3- is bonded in a 1-coordinate geometry to two equivalent K1+ and one C2+ atom. In the third N3- site, N3- is bonded in a 1-coordinate geometry to two equivalent K1+ and one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Magnetic excitations and absence of charge order in the van der Waals ferromagnet Fe 4.75 GeTe 2

Understanding the ground state of van der Waals (vdW) magnets is crucial for designing devices leveraging these platforms. Here, we investigate the magnetic excitations and charge order in Fe 4.75 GeTe 2 , a vdW ferromagnet with ≈ 315 K Curie temperature. Using Fe L 3 -edge resonant inelastic X-ray scattering, we observe a dual nature of magnetic excitations, comprising a coherent magnon and a broad non-dispersive continuum extending up to 150 meV, 50% higher than in Fe 2.72 GeTe 2 . The continuum intensity is sinusoidally modulated along the stacking direction L, with a period matching the inter-slab distance. Our results indicate that while the dual character of the magnetic excitations is generic to Fe-Ge-Te vdW magnets, Fe 4.75 GeTe 2 exhibits a longer out-of-plane magnetic correlation length, suggesting enhanced 3D magnetic character. Furthermore, resonant X-ray diffraction reveals that previously reported ±(1/3, 1/3, L) peaks originate from crystal structure rather than from charge order.

Ferromagnetism↗
DOE OSTI2020

Materials Data on K4Ge2Au7 by Materials Project

K4Au7Ge2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded in a 12-coordinate geometry to twelve Au atoms. There are a spread of K–Au bond distances ranging from 3.52–3.84 Å. In the second K site, K is bonded in a 9-coordinate geometry to nine equivalent Au atoms. There are three shorter (3.50 Å) and six longer (3.78 Å) K–Au bond lengths. There are two inequivalent Au sites. In the first Au site, Au is bonded to six equivalent K and six equivalent Au atoms to form edge-sharing AuK6Au6 cuboctahedra. All Au–Au bond lengths are 2.82 Å. In the second Au site, Au is bonded in a 1-coordinate geometry to six K, one Au, and one Ge atom. The Au–Ge bond length is 2.48 Å. Ge is bonded in a 3-coordinate geometry to three equivalent Au atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KNaCa2(SiO3)8 by Materials Project

KNaCa2(SiO3)8 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. K is bonded to eight O atoms to form distorted KO8 hexagonal bipyramids that share corners with four SiO4 tetrahedra and edges with four SiO4 tetrahedra. There are a spread of K–O bond distances ranging from 2.94–3.22 Å. Na is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Na–O bond distances ranging from 2.28–2.85 Å. There are two inequivalent Ca sites. In the first Ca site, Ca is bonded in a 5-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.21–3.05 Å. In the second Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share corners with five SiO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.26–2.44 Å. There are eight inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.65 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 octahedra, corners with three SiO4 tetrahedra, and an edgeedge with one KO8 hexagonal bipyramid. The corner-sharing octahedral tilt angles are 58°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 octahedra, corners with three SiO4 tetrahedra, and an edgeedge with one KO8 hexagonal bipyramid. The corner-sharing octahedral tilt angles are 56°. There are a spread of Si–O bond distances ranging from 1.60–1.67 Å. In the fourth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent KO8 hexagonal bipyramids and corners with four SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.64 Å. In the fifth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. There are a spread of Si–O bond distances ranging from 1.60–1.65 Å. In the sixth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 octahedra, corners with three SiO4 tetrahedra, and an edgeedge with one KO8 hexagonal bipyramid. The corner-sharing octahedral tilt angles are 48°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. In the seventh Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 octahedra, corners with three SiO4 tetrahedra, and an edgeedge with one KO8 hexagonal bipyramid. The corner-sharing octahedral tilt angles are 45°. There are a spread of Si–O bond distances ranging from 1.60–1.67 Å. In the eighth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent KO8 hexagonal bipyramids and corners with four SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.63 Å. There are twenty-four inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the second O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the third O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the fourth O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the fifth O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the sixth O site, O is bonded in a bent 150 degrees geometry to one K and two Si atoms. In the seventh O site, O is bonded in a 3-coordinate geometry to two Ca and one Si atom. In the eighth O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the ninth O site, O is bonded in a linear geometry to two Si atoms. In the tenth O site, O is bonded in a bent 120 degrees geometry to one Na and one Ca atom. In the eleventh O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the twelfth O site, O is bonded in a distorted trigonal non-coplanar geometry to one Na, one Ca, and one Si atom. In the thirteenth O site, O is bonded in a bent 120 degrees geometry to one K and one O atom. The O–O bond length is 1.23 Å. In the fourteenth O site, O is bonded in a single-bond geometry to one O atom. The O–O bond length is 1.23 Å. In the fifteenth O site, O is bonded in a 3-coordinate geometry to one Na, one Ca, and one O atom. In the sixteenth O site, O is bonded in a distorted trigonal non-coplanar geometry to one Na, one Ca, and one Si atom. In the seventeenth O site, O is bonded in a distorted trigonal pyramidal geometry to one Na, two Ca, and one Si atom. In the eighteenth O site, O is bonded in a distorted trigonal planar geometry to two Ca and one Si atom. In the nineteenth O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the twentieth O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the twenty-first O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the twenty-second O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the twenty-third O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the twenty-fourth O site, O is bonded in a bent 120 degrees geometry to one K and one O atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KICl2O by Materials Project

KOICl2 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. K is bonded in a 6-coordinate geometry to six equivalent Cl atoms. There are a spread of K–Cl bond distances ranging from 3.16–3.19 Å. O is bonded in a bent 120 degrees geometry to two equivalent I atoms. Both O–I bond lengths are 2.10 Å. I is bonded in a square co-planar geometry to two equivalent O and two equivalent Cl atoms. Both I–Cl bond lengths are 2.63 Å. Cl is bonded to three equivalent K and one I atom to form a mixture of edge and corner-sharing ClK3I trigonal pyramids.

36 MATERIALS SCIENCE↗
NASA NTRS1989

NbN/MgO/NbN edge-geometry tunnel junctions

The fabrication and low-frequency testing of the first edge-geometry NbN/MgO/NbN superconducting tunnel junctions are reported. The use of an edge geometry allows very small junction areas to be obtained, while the all-NbN electrodes permit operation at 8-10 K with a potential maximum operating frequency above 1 THz. Edge definition in the base NbN film was accomplished utilizing Ar ion milling with an Al2O3 milling mask, followed by a lower energy ion cleaning step. This process has produced all-refractory-material tunnel junctions with areas as small as 0.1 sq micron, resistance-area products less than 21 ohm sq micron, and subgap to normal state resistance ratios larger than 18.

Hunt, B. D.↗
NASA NTRS2016

The Inner Edge of the Habitable Zone for Synchronously Rotating Planets Around Low-Mass Stars Using General Circulation Models

Terrestrial planets at the inner edge of the habitable zone (HZ) of late-K and M-dwarf stars are expected to be in synchronous rotation, as a consequence of strong tidal interactions with their host stars. Previous global climate model (GCM) studies have shown that, for slowly rotating planets, strong convection at the substellar point can create optically thick water clouds, increasing the planetary albedo, and thus stabilizing the climate against a thermal runaway. However these studies did not use self-consistent orbital/rotational periods for synchronously rotating planets placed at different distances from the host star. Here we provide new estimates of the inner edge of the HZ for synchronously rotating terrestrial planets around late-K and M-dwarf stars using a 3D Earth-analog GCM with self-consistent relationships between stellar metallicity, stellar effective temperature, and the planetary orbital/rotational period. We find that both atmospheric dynamics and the efficacy of the substellar cloud deck are sensitive to the precise rotation rate of the planet. Around mid-to-late M-dwarf stars with low metallicity, planetary rotation rates at the inner edge of the HZ become faster, and the inner edge of the HZ is farther away from the host stars than in previous GCM studies. For an Earth-sized planet, the dynamical regime of the substellar clouds begins to transition as the rotation rate approaches ∼10 days. These faster rotation rates produce stronger zonal winds that encircle the planet and smear the substellar clouds around it, lowering the planetary albedo, and causing the onset of the water-vapor greenhouse climatic instability to occur at up to ∼25% lower incident stellar fluxes than found in previous GCM studies. For mid-to-late M-dwarf stars with high metallicity and for mid-K to early-M stars, we agree with previous studies.

Planet and satellite atmospheres↗