Quasiparticle self-consistent GW study of cuprates: electronic structure, model parameters, and the two-band theory for Tc

摘要

Despite decades of progress, an understanding of unconventionalsuperconductivity still remains elusive. An important open question is aboutthe material dependence of the superconducting properties. Using thequasiparticle self-consistent GW method, we re-examine the electronic structureof copper oxide high-Tc materials. We show that QSGW captures several importantfeatures, distinctive from the conventional LDA results. The energy levelsplitting between dx2-y2 and d3z2-r2 is significantly enlarged and the van Hovesingularity point is lowered. The calculated results compare better than LDAwith recent experimental results from resonant inelastic xray scattering andangle resolved photoemission experiments. This agreement with the experimentssupports the previously suggested two-band theory for the material dependenceof the superconducting transition temperature, Tc.