Substitution of Cu by Ni at Cu(2) (plane) sites in YBa2Cu3O7 has a weak effect on the Hall constant, but turns the thermopower negative. In contrast, substitution at Cu(1) (chain) sites by Co decreases the Hall number exponentially. The suppression of Tc is due to different mechanisms in the two cases. We discuss how doping affects the carrier density, and the evidence in favor of a filling factor of in the undoped system.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics