We present evidence for the existence of two close-lying, nearly parallel energy bands in the vicinity of the Fermi level in YBa2Cu3O7. The electrons in these bands are located in the Ba-O planes and have nearly no Cu-O chain or plane components. The higher band is partially unoccupied and the corresponding Fermi surface was recently measured by the de Haas van Alphen effect. We have calculated the extremal Fermi-surface areas and the results are in excellent agreement with experiment, when spin splitting in high magnetic field is taken into account. We show furthermore that interband transitions for in-plane polarizations are allowed between these two bands and that they result in a sharp peak at about 350 cm-1 in our calculated optical conductivity.
ASJC Scopus subject areas
- Condensed Matter Physics