Mass imbalance in the ionic Hubbard model: a DRMG study

TL;DR

This study uses the density matrix renormalization group method to analyze the phase transitions in a one-dimensional ionic Hubbard model with mass imbalance, revealing a continuous transition and a phase diagram based on entanglement entropy.

Contribution

It provides the first detailed numerical analysis of the phase diagram of the mass-imbalanced ionic Hubbard model using DMRG, contrasting previous mean-field results.

Findings

Quantum phase transition is continuous.

Maximum von Neumann entropy at critical points.

Phase diagram constructed from entanglement entropy.

Abstract

We investigated the ionic Hubbard model with mass imbalance in one dimension, using the density matrix renormalization group method. This model exhibits a band insulator phase and an antiferromagnetic one, both with a finite spin gap. We found that this quantum phase transition is continuous, unalike the previous mean-field theory result. The von Neumann block entropy is maximum at the critical points, a fact that we used to build the phase diagram.