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116 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ba2Gd(CuO2)4 by Materials Project

GdBa2Cu4O8 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. Ba2+ is bonded in a distorted q6 geometry to ten O2- atoms. There are four shorter (2.78 Å) and six longer (2.99 Å) Ba–O bond lengths. Gd3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.42 Å) and four longer (2.43 Å) Gd–O bond lengths. There are two inequivalent Cu+2.25+ sites. In the first Cu+2.25+ site, Cu+2.25+ is bonded to five O2- atoms to form corner-sharing CuO5 square pyramids. There are four shorter (1.97 Å) and one longer (2.29 Å) Cu–O bond lengths. In the second Cu+2.25+ site, Cu+2.25+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.84–1.96 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Ba2+ and two Cu+2.25+ atoms to form a mixture of distorted edge and corner-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles are 11°. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, two equivalent Gd3+, and two equivalent Cu+2.25+ atoms. In the third O2- site, O2- is bonded in a distorted T-shaped geometry to two equivalent Ba2+ and three equivalent Cu+2.25+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+, two equivalent Gd3+, and two equivalent Cu+2.25+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba4Ca8Cu11CO20 by Materials Project

(Ba2Ca4(CuO2)5)2CuC crystallizes in the tetragonal I4/mmm space group. The structure is two-dimensional and consists of two copper molecules; two methane molecules; and two Ba2Ca4(CuO2)5 sheets oriented in the (0, 0, 1) direction. In each Ba2Ca4(CuO2)5 sheet, Ba2+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Ba–O bond lengths are 2.65 Å. There are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.49 Å) and four longer (2.58 Å) Ca–O bond lengths. In the second Ca2+ site, Ca2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.51 Å) and four longer (2.54 Å) Ca–O bond lengths. There are five inequivalent Cu+1.09+ sites. In the first Cu+1.09+ site, Cu+1.09+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.96 Å. In the second Cu+1.09+ site, Cu+1.09+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.96 Å. In the third Cu+1.09+ site, Cu+1.09+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.97 Å. In the fourth Cu+1.09+ site, Cu+1.09+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.97 Å. In the fifth Cu+1.09+ site, Cu+1.09+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.97 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ca2+ and two Cu+1.09+ atoms to form OCa4Cu2 octahedra that share corners with fourteen OBa2Ca2Cu2 octahedra, edges with four OBa2Ca2Cu2 octahedra, and faces with four equivalent OCa4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 1–67°. In the second O2- site, O2- is bonded to two equivalent Ba2+, two equivalent Ca2+, and two Cu+1.09+ atoms to form a mixture of distorted edge, face, and corner-sharing OBa2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 3–67°. In the third O2- site, O2- is bonded to four equivalent Ca2+ and two equivalent Cu+1.09+ atoms to form a mixture of edge, face, and corner-sharing OCa4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–67°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cu(CO4)2 by Materials Project

CuO2(CO2)2O2 is Cyanogen Chloride-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of four carbon dioxide molecules; two hydrogen peroxide molecules; and two CuO2 ribbons oriented in the (1, 0, 0) direction. In each CuO2 ribbon, Cu is bonded in a linear geometry to two equivalent O atoms. Both Cu–O bond lengths are 1.82 Å. O is bonded in a distorted bent 120 degrees geometry to one Cu and one O atom. The O–O bond length is 1.39 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaCa2Cu3O5 by Materials Project

Ba2Ca4(CuO2)5Cu crystallizes in the tetragonal P4/mmm space group. The structure is two-dimensional and consists of one cuprum molecule and one Ba2Ca4(CuO2)5 sheet oriented in the (0, 0, 1) direction. In the Ba2Ca4(CuO2)5 sheet, Ba2+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Ba–O bond lengths are 2.61 Å. There are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.52 Å) and four longer (2.56 Å) Ca–O bond lengths. In the second Ca2+ site, Ca2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.47 Å) and four longer (2.62 Å) Ca–O bond lengths. There are three inequivalent Cu+1.33+ sites. In the first Cu+1.33+ site, Cu+1.33+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.98 Å. In the second Cu+1.33+ site, Cu+1.33+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.97 Å. In the third Cu+1.33+ site, Cu+1.33+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.97 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Ba2+, two equivalent Ca2+, and two equivalent Cu+1.33+ atoms to form distorted OBa2Ca2Cu2 octahedra that share corners with eight OCa4Cu2 octahedra, edges with three OCa4Cu2 octahedra, and faces with four equivalent OBa2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 4–67°. In the second O2- site, O2- is bonded to four Ca2+ and two equivalent Cu+1.33+ atoms to form a mixture of face, edge, and corner-sharing OCa4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 1–67°. In the third O2- site, O2- is bonded to four equivalent Ca2+ and two equivalent Cu+1.33+ atoms to form a mixture of face, edge, and corner-sharing OCa4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–67°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cu(CO4)2 by Materials Project

CuO2(CO2)2O2 is Cyanogen Chloride-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of four carbon dioxide molecules; two hydrogen peroxide molecules; and two CuO2 ribbons oriented in the (1, 0, 0) direction. In each CuO2 ribbon, Cu is bonded in a linear geometry to two equivalent O atoms. Both Cu–O bond lengths are 1.81 Å. O is bonded in a distorted bent 120 degrees geometry to one Cu and one O atom. The O–O bond length is 1.39 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Structure of Charge Density Waves in La1.875Ba0.125CuO4

Although charge-density wave (CDW) correlations exist in several families of cuprate superconductors, they exhibit substantial variation in CDW wavevector and correlation length, indicating a key role for CDW-lattice interactions. We investigated this interaction in La1.875Ba0.125CuO4 using single crystal x-ray diffraction to collect a large number of CDW peak intensities, and determined the Cu and La/Ba atomic distortions induced by the formation of CDW order. Within the CuO2 planes, the distortions involve a periodic modulation of the Cu-Cu spacing along the direction of the ordering wave vector. The charge ordering within the copper-oxygen layer induces an out-of-plane breathing modulation of the surrounding lanthanum layers, which leads to a related distortion on the adjacent copper-oxygen layer. Our result implies that the CDW-related structural distortions do not remain confined to a single layer but rather propagate an appreciable distance through the crystal. This leads to overlapping structural modulations, in which CuO2 planes exhibit distortions arising from the orthogonal CDWs in adjacent layers as well as distortions from the CDW within the layer itself. We attribute this striking effect to the weak c-axis charge screening in cuprates and suggest this effect could help couple the CDW between adjacent planes in the crystal.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Materials Data on CuC4(NO2)4 by Materials Project

CuO2(N2CO)2(CO2)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four carbon dioxide molecules, two copper(ii) hydroxide molecules, and four N2CO clusters. In each N2CO cluster, C4+ is bonded in a 1-coordinate geometry to two N+0.50- and one O2- atom. Both C–N bond lengths are 1.40 Å. The C–O bond length is 1.20 Å. There are two inequivalent N+0.50- sites. In the first N+0.50- site, N+0.50- is bonded in a 1-coordinate geometry to one C4+ and one N+0.50- atom. The N–N bond length is 1.32 Å. In the second N+0.50- site, N+0.50- is bonded in a 1-coordinate geometry to one C4+ and one N+0.50- atom. O2- is bonded in a single-bond geometry to one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Extremely Overdoped Superconducting Cuprates via High Pressure Oxygenation Methods

Within the cuprate constellation, one fixed star has been the superconducting dome in the quantum phase diagram of transition temperature vs. the excess charge on the Cu in the CuO2-planes, p, resulting from O-doping or cation substitution. However, a more extensive search of the literature shows that the loss of the superconductivity in favor of a normal Fermi liquid on the overdoped side should not be assumed. Many experimental results from cuprates prepared by high-pressure oxygenation show Tc converging to a fixed value or continuing to slowly increase past the upper limit of the dome of p = 0.26–0.27, up to the maximum amounts of excess oxygen corresponding to p values of 0.3 to > 0.6. These reports have been met with disinterest or disregard. Our review shows that dome-breaking trends for Tc are, in fact, the result of careful, accurate experimental work on a large number of compounds. This behavior most likely mandates a revision of the theoretical basis for high-temperature superconductivity. That excess O atoms located in specific, metastable sites in the crystal, attainable only with extreme O chemical activity under HPO conditions, cause such a radical extension of the superconductivity points to a much more substantial role for the lattice in terms of internal chemistry and bonding.

Sederholm, Linda (ORCID:0000000172090509)↗