Antiferromagnetism and single-particle properties in the two-dimensional half-filled Hubbard model: Slater vs Mott-Heisenberg

TL;DR

This paper investigates how antiferromagnetism and single-particle properties evolve in the 2D half-filled Hubbard model, revealing a transition from Slater to Mott-Heisenberg behavior and a finite-temperature metal-insulator transition.

Contribution

It derives a non-linear sigma model from the Hubbard model applicable at any Coulomb repulsion, elucidating the evolution of ground states and finite-temperature phase transitions.

Findings

Ground state transitions from Slater to Mott-Heisenberg antiferromagnet with increasing Coulomb repulsion.

Identification of a metal-insulator transition at finite temperature between pseudogap and Mott-Hubbard insulator phases.

Derivation of a non-linear sigma model governing collective spin fluctuations across interaction regimes.

Abstract

We study antiferromagnetism and single-particle properties in the two-dimensional half-filled Hubbard model at low temperature. Collective spin fluctuations are governed by a non-linear sigma model that we derive from the Hubbard model for any value of the Coulomb repulsion. As the Coulomb repulsion increases, the ground state progressively evolves from a Slater to a Mott-Heisenberg antiferromagnet. At finite temperature, we find a metal-insulator transition between a pseudogap phase at weak coupling and a Mott-Hubbard insulator at strong coupling.