Anisotropy and carrier distribution in HgBa2Can-1CunO2n+2 (n=3,4)

The electronic structure of HgBa2Can-1CunO2n+2 (n=3,4, Hg12(n-1)n) is investigated by using the scalar-relativistic full-potential linearized augmented-plane-wave method. We calculated Fermi velocities vF and Fermi surface volume, and found that the anisotropy defined by the ratio vFx/vFz is similar to that in TlBa2Ca2Cu3O9. This anisotropy is also in good agreement with the experimental value. Each of the large Fermi surfaces contains 0.93-1.11 holes in Hg1223 and 0.90-1.14 holes in Hg1234. These values are similar to that in CuBa2Ca3Cu4O9F, which are designed to have an optimum set of the Fermi surface for superconductivity