A comparative study of the electronic structure of the high-Tcsuperconductor YBa2Cu3O7in its two proposed crystal structures

Abstract

The authors have investigated the electronic structure of YBa2Cu3O7 in its generally accepted crystal structure, and the one proposed recently by Reller, Bednorz and Muller. Overall, the electronic structures are quite similar, but there are differences in details, especially at the Fermi level. Although the total densities of states at the Fermi level are about the same in the two crystal structures (about 3 states per eV-unit cell), the repartition at different local atomic sites is substantially different. They find that the structure proposed by Reller and co-workers also presents substantial anisotropy along the c-axis in the electronic structure.