Dynamical density matrix renormalization group study of photoexcited states in one-dimensional Mott insulators

TL;DR

This study uses the dynamical density matrix renormalization group method to analyze photoexcited states and optical responses in one-dimensional Mott insulators, revealing how Coulomb interactions influence state degeneracy and optical properties.

Contribution

It introduces a detailed analysis of photoexcited states in 1D Mott insulators considering Coulomb interactions using DMRG, highlighting the degeneracy and bound state formation.

Findings

Degeneracy of excited states for V/t mpl 2

Formation of bound states with different parities for V/t mpl 2

Impact of Coulomb interactions on optical response

Abstract

One-dimensional Mott insulators exhibit giant nonlinear optical response. Based on the dynamical density matrix renormalization group method, photoexcited states and optical response in the insulators are studied as functions of the on-site and the nearest neighbor Coulomb interactions, $U$ and $V$, respectively. We find that the lowest optically-allowed and forbidden excited states, which have odd and even parities, respectively, are degenerate for $V/t\ltsim 2$ with $t$ being the hopping integral of an electron between nearest neighbor sites. For $V/t\gtsim 2$, the bound states with even and odd parities occur and are not degenerate. The nature of the degeneracy and its effect on the optical response are examined.