Density matrix renormalization group study of optical conductivity in the one-dimensional Mott insulator Sr_2CuO_3

TL;DR

This study uses advanced density matrix renormalization group methods to analyze the optical conductivity of Sr_2CuO_3, revealing the effects of electron-phonon interactions on Mott-gap and spin excitations.

Contribution

It introduces a detailed Hubbard-Holstein model analysis of optical conductivity in a one-dimensional Mott insulator using dynamical DMRG techniques.

Findings

Model parameters reproduce high-energy Mott-gap excitation.

Electron-phonon interaction causes broadening of spectral features.

Temperature dependence of excitations is affected by phonon interactions.

Abstract

Applying newly developed dynamical density matrix renormalization group techniques at zero and finite temperatures to a Hubbard-Holstein model at half-filling, we examine the optical conductivity of a typical one-dimensional Mott insulator Sr_2CuO_3. We find a set of parameters in the Hubbard-Holstein model, which can describe optical conductivity for both Mott-gap excitation in the high-energy region and phonon-assisted spin excitation in the low-energy region. We also find that electron-phonon interaction gives additional broadening in the temperature dependence of the Mott-gap excitation.