Doping and temperature evolution of pseudogap and spin-spin correlations in the two-dimensional Hubbard model
V. I. Kuz’min, Maxim A. Visotin, С. В. Николаев, С. Г. Овчинников
Abstract
Cluster perturbation theory is applied to the two-dimensional Hubbard $t\ensuremath{-}{t}^{\ensuremath{'}}\ensuremath{-}{t}^{\ensuremath{'}\ensuremath{'}}\ensuremath{-}U$ model to obtain doping and temperature-dependent electronic spectral function with $4\ifmmode\times\else\texttimes\fi{}4$ and 12-site clusters. It is shown that evolution of the pseudogap and electronic dispersion with doping and temperature is similar and in both cases it is significantly influenced by spin-spin short-range correlations. When short-range magnetic order is weakened by doping or temperature and Hubbard-I-like electronic dispersion becomes more pronounced, the Fermi arc turns into a large Fermi surface and the pseudogap closes. It is demonstrated how static spin correlations impact the overall dispersion's shape and how accounting for dynamic contributions leads to momentum-dependent spectral weight at the Fermi surface and broadening effects.