Pseudogap formation in the half-filled Hubbard model

Abstract

Using quantum Monte Carlo, we study the evolution of pseudogaps in the spectral weight function for a half-filled two-dimensional Hubbard model as a function of temperature and coupling constant. The formation of pseudogaps at finite temperature can be used to distinguish between three regimes: (1) a strong-coupling Mott-Hubbard regime, characterized by a pseudogap which persists even at high temperatures; (2) a weak-coupling spin-density-wave regime, characterized by the absence of a pseudogap at any finite temperature; and (3) an intermediate-coupling regime with mixed behavior, characterized by a pseudogap that appears at a finite temperature.