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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ca(CuO2)2 by Materials Project

Ca(CuO2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.38–2.48 Å. There are two inequivalent Cu3+ sites. In the first Cu3+ site, Cu3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing CuO6 octahedra. The corner-sharing octahedra tilt angles range from 49–58°. There are a spread of Cu–O bond distances ranging from 1.99–2.05 Å. In the second Cu3+ site, Cu3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing CuO6 octahedra. The corner-sharing octahedra tilt angles range from 49–58°. There are a spread of Cu–O bond distances ranging from 1.97–2.08 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Ca2+ and three equivalent Cu3+ atoms. In the second O2- site, O2- is bonded to two equivalent Ca2+ and three Cu3+ atoms to form a mixture of distorted edge and corner-sharing OCa2Cu3 trigonal bipyramids. In the third O2- site, O2- is bonded to two equivalent Ca2+ and three equivalent Cu3+ atoms to form a mixture of distorted edge and corner-sharing OCa2Cu3 square pyramids. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Ca2+ and three Cu3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(CuO2)2 by Materials Project

Ca(CuO2)2 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.26–2.83 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.25–2.83 Å. There are four inequivalent Cu3+ sites. In the first Cu3+ site, Cu3+ is bonded to five O2- atoms to form CuO5 square pyramids that share corners with four CuO6 octahedra and edges with two equivalent CuO5 square pyramids. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Cu–O bond distances ranging from 1.91–2.06 Å. In the second Cu3+ site, Cu3+ is bonded to six O2- atoms to form CuO6 octahedra that share corners with four CuO5 square pyramids and edges with four CuO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.95–2.05 Å. In the third Cu3+ site, Cu3+ is bonded to six O2- atoms to form CuO6 octahedra that share corners with four CuO5 square pyramids and edges with four CuO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.95–2.06 Å. In the fourth Cu3+ site, Cu3+ is bonded to five O2- atoms to form CuO5 square pyramids that share corners with four CuO6 octahedra and edges with two equivalent CuO5 square pyramids. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Cu–O bond distances ranging from 1.91–2.07 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+ and three Cu3+ atoms. In the second O2- site, O2- is bonded to one Ca2+ and three Cu3+ atoms to form distorted OCaCu3 trigonal pyramids that share corners with two equivalent OCa2Cu3 square pyramids, corners with two equivalent OCaCu3 trigonal pyramids, and edges with three OCa2Cu3 square pyramids. In the third O2- site, O2- is bonded to one Ca2+ and three Cu3+ atoms to form distorted OCaCu3 trigonal pyramids that share corners with two equivalent OCa2Cu3 square pyramids, corners with two equivalent OCaCu3 trigonal pyramids, and edges with three OCa2Cu3 square pyramids. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+ and three Cu3+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Ca2+ and two equivalent Cu3+ atoms. In the sixth O2- site, O2- is bonded to two equivalent Ca2+ and three Cu3+ atoms to form OCa2Cu3 square pyramids that share corners with two equivalent OCaCu3 trigonal pyramids, edges with four OCa2Cu3 square pyramids, and edges with three OCaCu3 trigonal pyramids. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Ca2+ and two equivalent Cu3+ atoms. In the eighth O2- site, O2- is bonded to two equivalent Ca2+ and three Cu3+ atoms to form OCa2Cu3 square pyramids that share corners with two equivalent OCaCu3 trigonal pyramids, edges with four OCa2Cu3 square pyramids, and edges with three OCaCu3 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(CuO2)2 by Materials Project

Ca2CuO2(CuO2)3 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of three copper(ii) hydroxide molecules and one Ca2CuO2 cluster. In the Ca2CuO2 cluster, Ca2+ is bonded in a 1-coordinate geometry to one O2- atom. The Ca–O bond length is 1.54 Å. Cu3+ is bonded in a distorted linear geometry to two equivalent O2- atoms. Both Cu–O bond lengths are 1.57 Å. O2- is bonded in a distorted L-shaped geometry to one Ca2+ and one Cu3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(CuO2)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SrCa(CuO2)2 by Materials Project

SrCa(CuO2)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sr2+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Sr–O bond lengths are 2.58 Å. Ca2+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Ca–O bond lengths are 2.58 Å. Cu2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.96 Å. O2- is bonded to two equivalent Sr2+, two equivalent Ca2+, and two equivalent Cu2+ atoms to form a mixture of corner, edge, and face-sharing OSr2Ca2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–65°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SrCa(CuO2)2 by Materials Project

SrCa(CuO2)2 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Sr2+ is bonded to seven O2- atoms to form distorted SrO7 pentagonal bipyramids that share corners with four equivalent SrO7 pentagonal bipyramids, edges with two equivalent SrO7 pentagonal bipyramids, edges with four equivalent CaO7 pentagonal bipyramids, and faces with two equivalent SrO7 pentagonal bipyramids. There are a spread of Sr–O bond distances ranging from 2.42–2.65 Å. Ca2+ is bonded to seven O2- atoms to form distorted CaO7 pentagonal bipyramids that share corners with four equivalent CaO7 pentagonal bipyramids, edges with two equivalent CaO7 pentagonal bipyramids, edges with four equivalent SrO7 pentagonal bipyramids, and faces with two equivalent CaO7 pentagonal bipyramids. There are a spread of Ca–O bond distances ranging from 2.38–2.64 Å. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.88–1.97 Å. In the second Cu2+ site, Cu2+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.95–1.97 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Sr2+ and three Cu2+ atoms to form OSr2Cu3 trigonal bipyramids that share corners with seven OSrCa4Cu octahedra, corners with four equivalent OSr2Cu3 trigonal bipyramids, edges with two equivalent OCa2Cu3 trigonal bipyramids, and faces with two equivalent OSr4CaCu octahedra. The corner-sharing octahedra tilt angles range from 0–59°. In the second O2- site, O2- is bonded to two equivalent Ca2+ and three Cu2+ atoms to form OCa2Cu3 trigonal bipyramids that share corners with seven OSrCa4Cu octahedra, corners with four equivalent OCa2Cu3 trigonal bipyramids, edges with two equivalent OSr2Cu3 trigonal bipyramids, and faces with two equivalent OSrCa4Cu octahedra. The corner-sharing octahedra tilt angles range from 0–59°. In the third O2- site, O2- is bonded to one Sr2+, four equivalent Ca2+, and one Cu2+ atom to form distorted OSrCa4Cu octahedra that share corners with four equivalent OSrCa4Cu octahedra, corners with seven OSr2Cu3 trigonal bipyramids, edges with eight OSrCa4Cu octahedra, and faces with two equivalent OCa2Cu3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 8°. In the fourth O2- site, O2- is bonded to four equivalent Sr2+, one Ca2+, and one Cu2+ atom to form distorted OSr4CaCu octahedra that share corners with four equivalent OSr4CaCu octahedra, corners with seven OSr2Cu3 trigonal bipyramids, edges with eight OSrCa4Cu octahedra, and faces with two equivalent OSr2Cu3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 10°.

36 MATERIALS SCIENCE↗
NASA NTRS1995

Structural, dynamical and electronic properties of CaCuO2

The scalar relativistic version of an accurate first principles full potential self-consistent linearized muffin tin orbital (LMTO) method has been employed for describing the physical properties of the parent system of the high-T(sub c) oxide superconductors, i.e., CaCuO2. The presently employed modified version of the LMTO method is quite fast and goes beyond the usual LMTO ASA method in the sense that it permits a completely general shape of the potential and the charge density. Also, in contrast to LMTO ASA, the present method is also capable of treating distorted lattice structures accurately. The calculated values of the lattice parameters of pure CaCuO2 lie within 3% of the experimentally measured values for the Sr-doped system Ca(0.86)Sr(0.14)CuO(2). The computed electronic structures and the density of states is quite similar to those of the other oxide superconductors, except of their three- dimensional character because of the presence of strong coupling between the closely spaced CuO2 layers. The van Hove singularity peak appears slightly below the Fermi level and a small concentration of oxygenation /or/ substitutional doping may pin it at the Fermi level. The calculated frequencies for some symmetric frozen phonons for undoped CaCuO2 are quite near to the measured data for the Sr-doped CaCuO2.

Agrawal, Bal K.↗