Photoemission measurements have been performed on the high-Tc superconductor YBa2Cu3O6.85 using synchrotron radiation of 20- 110 eV. It is found that the valence band is shifted by 1.1 to 1.6 eV towards higher binding energy relative to band calculations. The effective intraatomic Coulomb energy between d electrons (Udd) was evaluated from the energy position of the valence-band satellite due to the two-hole bound state: Udd=5-6 eV, which is comparable to the valence-band width (W=6-7 eV). This strongly suggests that electron correlation plays a key role in characterizing the electronic properties of this oxide superconductor.
ASJC Scopus subject areas
- Condensed Matter Physics