Spectral Properties of Correlated Materials: Local Vertex and Non-Local Two-Particle Correlations from Combined GW and Dynamical Mean Field Theory

TL;DR

This paper combines GW and DMFT methods to improve the understanding of spectral and collective properties in correlated two-dimensional materials, revealing enhanced spectral features and dispersive collective modes.

Contribution

It introduces a fully self-consistent GW+DMFT approach that incorporates local vertex corrections, improving spectral and collective mode descriptions in correlated materials.

Findings

GW+DMFT narrows quasi-particle widths near charge transition

Enhanced Hubbard bands observed with GW inclusion

Dispersive plasmon-like and stripe modes identified

Abstract

We present a fully self-consistent combined GW and dynamical mean field (GW+DMFT) study of the spectral properties of the extended two-dimensional Hubbard model. The inclusion of the local dynamical vertex stemming from the DMFT self-energy and polarization is shown to cure the problems of self-consistent GW in the description of spectral properties. We calculate the momentum-resolved spectral functions, the two-particle polarization and electron loss spectra, and show that the inclusion of GW in extended DMFT leads to a narrowing of the quasi-particle width and more pronounced Hubbard bands in the metallic regime as one approaches the charge-ordering transition. Finally, the momentum-dependence introduced by GW into the extended DMFT description of collective modes is found to affect their shape, giving rise to dispersive plasmon-like long-wavelength and stripe modes.