Electron-phonon coupling and spin-charge separation in one-dimensional Mott insulators

TL;DR

This paper investigates how electron-phonon interactions affect spin-charge separation in one-dimensional Mott insulators, revealing robustness of separation against phonons and contrasting with higher-dimensional systems.

Contribution

It demonstrates that spin-charge separation persists in the 1D Hubbard-Holstein model despite electron-phonon coupling, using DDMRG calculations and spectral analysis.

Findings

Spin-charge separation remains robust with electron-phonon coupling.

Spectra interpreted as a superposition of spinless carriers dressed with phonons.

Contrasts with phonon-spin coupling in two-dimensional systems.

Abstract

We examine the single-particle excitation spectrum in the one-dimensional Hubbard-Holstein model at half-filling by performing the dynamical density matrix renormalization group (DDMRG) calculation. The DDMRG results are interpreted as superposition of spectra for a spinless carrier dressed with phonons. The superposition is a consequence of robustness of the spin-charge separation against electron-phonon coupling. The separation is in contrast to the coupling between phonon and spin degrees of freedom in two-dimensional systems. We discuss implication of the results of the recent angle-resolved photoemission spectroscopy measurements on SrCuO${}_{2}$.