Finite-temperature phase diagram of the Hubbard model

Abstract

The finite-temperature phase diagram of the Hubbard model in d=3 is obtained from renormalization-group analysis. It exhibits, around half filling, an antiferromagnetic phase and, between 30%-40% electron or hole doping from half filling, a new τ phase in which the electron hopping strength t asymptotically becomes infinite under repeated rescalings. Next to the τ phase, a first-order phase boundary with very narrow phase separation (less than 2% jump in electron density) occurs. At temperatures above the τ phase, an incommensurate spin modulation phase is indicated. In d=2, we find that the Hubbard model has no phase transition at finite temperature.