First order Mott transition at zero temperature in two dimensions: Variational plaquette study

TL;DR

This study uses a variational cluster approach to demonstrate that the zero-temperature Mott transition in a 2D Hubbard model is first order, highlighting the importance of short-range correlations in the transition's nature.

Contribution

It provides evidence that the zero-temperature Mott transition in two dimensions is first order, contrasting with previous theories suggesting a quantum critical point.

Findings

Transition is first order at zero temperature.

Antiferromagnetic short-range correlations influence the transition.

Contrasts with single-site dynamical mean-field theory results.

Abstract

The nature of the metal-insulator Mott transition at zero temperature has been discussed for a number of years. Whether it occurs through a quantum critical point or through a first order transition is expected to profoundly influence the nature of the finite temperature phase diagram. In this paper, we study the zero temperature Mott transition in the two-dimensional Hubbard model on the square lattice with the variational cluster approximation. This takes into account the influence of antiferromagnetic short-range correlations. By contrast to single-site dynamical mean-field theory, the transition turns out to be first order even at zero temperature.