Phase separation in the particle-hole asymmetric Hubbard model

TL;DR

This paper investigates how next-nearest-neighbor hopping breaks particle-hole symmetry in the Hubbard model, leading to phase separation and suppressed Mott transition temperature, using dynamical mean-field theory on the Bethe lattice.

Contribution

It provides the first detailed analysis of phase separation in the particle-hole asymmetric Hubbard model with NNN hopping on the Bethe lattice.

Findings

Phase separation occurs near half-filling.

Particle-hole asymmetry causes strong electron-hole doping differences.

Critical temperature of the Mott transition is significantly suppressed.

Abstract

The paramagnetic phase diagram of the Hubbard model with nearest-neighbor (NN) and next-nearest-neighbor (NNN) hopping on the Bethe lattice is computed at half-filling and in the weakly doped regime using the self-energy functional approach for dynamical mean-field theory. NNN hopping breaks the particle-hole symmetry and leads to a strong asymmetry of the electron-doped and hole-doped regimes. Phase separation occurs at and near half-filling, and the critical temperature of the Mott transition is strongly suppressed.