Mott Transition in Quasi-One-Dimensional Systems

TL;DR

This paper uses the density-matrix renormalization group method to study a quasi-one-dimensional Hubbard model, revealing a transition from insulator to metal driven by transverse hopping, and a subsequent metal-insulator transition at finite interaction strength.

Contribution

It demonstrates the application of DMRG to a 2D Hubbard model, uncovering a deconfinement transition and contrasting with Hartree-Fock predictions.

Findings

Deconfinement transition from insulator to metal with increasing $t_y$

Metal-insulator transition at finite $U$ when $t_y$ is fixed in the metallic phase

Contradicts Hartree-Fock theory predicting insulator for any $U>0$

Abstract

We report the application of the density-matrix renormalization group method to a spatially anisotropic two-dimensional Hubbard model at half-filling. We find a deconfinement transition induced by the transverse hopping parameter $t_y$ from an insulator to a metal. Therefore, if $t_y$ is fixed in the metallic phase, increasing the interaction $U$ leads to a metal-to-insulator transition at a finite critical $U$. This is in contrast to the weak-coupling Hartree-Fock theory which predicts a nesting induced antiferromagnetic insulator for any $U>0$.