Phase transitions and spectral properties of the ionic Hubbard model in one dimension

TL;DR

This paper studies the phase transitions and spectral features of the one-dimensional ionic Hubbard model at half filling, using cellular dynamical mean-field theory to identify insulating phases and spectral characteristics.

Contribution

It introduces the renormalized band gap as an order parameter and analyzes spectral properties across interaction regimes.

Findings

Transition from band insulator to Mott insulator identified

Renormalized band gap effectively signals phase transition

Spectral features differ markedly between weak and strong interactions

Abstract

The ionic Hubbard model is investigated at half filling at zero temperature. We apply the cellular dynamical mean-field theory to the one-dimensional ionic Hubbard model to compute local quantities such as double occupancy and staggered charge density. Both quantities provide general transition behavior of the model from a band insulating phase to a Mott insulating phase. The renormalized band gap is introduced as an efficient order parameter for the transition from a band insulator. We also present the spectral properties of the ionic Hubbard model, which exhibit characteristic features for both weak and strong interactions.