Dynamical Screening Effects in Correlated Electron Materials -- A Progress Report on Combined Many-Body Perturbation and Dynamical Mean Field Theory: "GW+DMFT"

TL;DR

This paper reviews recent advances in first-principles electronic structure methods for strongly correlated materials, focusing on dynamical screening effects and the development of GW+DMFT, a combined approach that incorporates dynamical Coulomb interactions.

Contribution

It introduces and discusses the recent development of GW+DMFT, integrating many-body perturbation theory with dynamical mean field theory to account for dynamical screening in correlated materials.

Findings

First GW+DMFT calculations for real materials like SrVO3

Inclusion of dynamical Coulomb interactions U(w) in simulations

Enhanced understanding of screening effects in correlated electron systems

Abstract

We give a summary of recent progress in the field of electronic structure calculations for materials with strong electronic Coulomb correlations. The discussion focuses on developments beyond the by now well established combination of density functional and dynamical mean field theory dubbed "LDA+DMFT". It is organized around the description of dynamical screening effects in the solid. Indeed, screening in the solid gives rise to dynamical local Coulomb interactions U(w) (Aryasetiawan et al 2004 Phys. Rev. B 70 195104), and this frequency-dependence leads to effects that cannot be neglected in a truly first principles description. We review the recently introduced extension of LDA+DMFT to dynamical local Coulomb interactions "LDA+U(w)+DMFT" (Casula et al. Phys. Rev. B 85 035115 (2012), Werner et al. Nature Phys. 8 331 (2012)). A reliable description of dynamical screening effects is also a central ingredient of the "GW+DMFT" scheme (Biermann et al. Phys. Rev. Lett. 90 086402 (2003)), a combination of many-body perturbation theory in Hedin's GW approximation and dynamical mean field theory. Recently, the first GW+DMFT calculations including dynamical screening effects for real materials have been achieved, with applications to SrVO3 (Tomczak et al. Europhys. Lett. 100 67001 (2012); Phys. Rev. B 90 165138 (2014)) and adatom systems on surfaces (Hansmann et al. Phys. Rev. Lett. 110 166401 (2013)). We review these and comment on further perspectives in the field. This review is an attempt to put elements of the original works (Refs. 1-11) into the broad perspective of the development of truly first principles techniques for correlated electron materials.