Study of the ionic Peierls-Hubbard model using density matrix renormalization group methods

TL;DR

This study uses density matrix renormalization group methods to explore the phase diagram of a one-dimensional ionic Hubbard model with electron-phonon interactions, revealing a persistent bond order wave phase influenced by multiple interactions.

Contribution

It provides a detailed quantum phase diagram of the ionic Peierls-Hubbard model, highlighting the role of electron-electron, ionic potential, and phonon fluctuations in phase formation.

Findings

Bond order wave phase exists with electron-phonon coupling.

Phase diagram differs from adiabatic limit behavior.

Electron interactions and phonons jointly influence phase stability.

Abstract

Density matrix renormalization group methods are used to investigate the quantum phase diagram of a one-dimensional half-filled ionic Hubbard model with bond-charge attraction, which can be mapped from the Su-Schrieffer-Heeger-type electron-phonon coupling at the antiadiabatic limit. A bond order wave (dimerized) phase which separates the band insulator from the Mott insulator always exists as long as electron-phonon coupling is present. This is qualitatively different from that at the adiabatic limit. Our results indicate that electron-electron interaction, ionic potential and quantum phonon fluctuations combine in the formation of the bond-order wave phase.