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Order-disorder-driven change in hole concentration and superconductivity in YBa2Cu3O6.5

Raju P. Gupta, Michèle Gupta

DOI 10.1103/PhysRevB.44.2739 · Physical Review B

T1

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Abstract

The results of electronic-structure calculations for the compound YBa2Cu3O6.5 are presented in order to understand the role that the ordering of oxygen atoms in the plane of the chains plays in the charge transfer from the CuO2 planes to the plane of the chains. Three models of crystal structure for YBa2Cu3O6.5 have been considered for this purpose: (a) an alternate-chain model where each alternate chain is fully intact and the adjacent one fully empty, (b) an identical-chain model where all chains are identical but broken, and (c) a tetragonal crystal structure. We find that practically no charge transfer occurs from the CuO2 planes towards the plane of the chains in the latter two models, while in the first ∼0.16 electrons CuO2 planes are transferred. This shows that ordered chains are important for hole creation and superconductivity.

Source-reported materials — not catalogue approval

FormulaReported Tc (K)Pressure (GPa)Type
YBa2Cu3O7-δ

Archive — visibility unverified

Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.

90Pressure not reportedunknown
YBa2Cu3O6.5

Archive — visibility unverified

Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.

60Pressure not reportedunknown

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