Electronic structure and properties of vacancy-ordered YBa2Cu3O6.5: Chain versus plane Fermi surfaces in YBa2Cu3O7-δ

✍ Scribed by Jaejun Yu; S. Massidda; A.J. Freeman; R. Podloucky

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 736 KB
• Volume: 214
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(93)90835-e

✦ Synopsis

Results of local density calculations of the electronic structure for vacancy-ordered YBa2Cu306.5 using the highly precise fullpotential linearized augmented-plane-wave (FLAPW) method are presented. For a model structure of the vacancy-ordering in YBa2Cu3Or.5 with a "full-and empty-chain" configuration in the Cu( 1 ) chain plane, detailed analyses of energy hands, density of states, Fermi surface, and electron-phonon interaction parameters are made and compared with results for YBa2Cu307 and YBa2Cu3Or. The 2D dpo Cu (2) plane bands crossing EF are found to he insensitive to the oxygen stoichiometry or ordering in the Cu( l ) chain; on the other hand, the formation of the ordered Cu-O chains in the Cu( l ) plane is crucial in the determination of the chain electronic structure near EF. Thus, it is shown that both the ordering of oxygens (i.e., formation of chains) in the Cu ( 1 ) plane as well as the oxygen content (i.e., ~) are important in understanding the band-filling of the 2D dp6 bands and the observed metallic behavior in YBa2Cu307_6, where the Cu-O chains play the roles not only as a charge reservoir but also as a metallic chain. We also present the calculated FS in the "vacancy-ordered" YBa2Cu306.5, which agrees with a recent photoemission experiment.