1 Scientific Highlight of the Month

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(ω) [1, 2], and this frequency-dependence leads to effects that cannot be neglected in a truly first principles description [3]. We review the recently introduced extension of LDA+DMFT to dynamical local Coulomb interactions “LDA+U(ω)+DMFT” [4, 5]. A reliable description of dynamical screening effects is also a central ingredient of the “GW+DMFT” scheme [6, 7, 8], 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 [9] and adatom systems on surfaces [10]. We review these and comment on further perspectives in the field. This review is an attempt to put elements of the original works [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] into the broad perspective of the development of truly first principles techniques for correlated electron materials. 1 Electronic Correlations from First Principles? The electronic properties of solids are dominated by the electronic states in the immediate proximity to the Fermi level. This observation – together with the insights from renormalisation group techniques – are the motivation for the quest of low-energy effective models that describe the physical phenomena taking place in condensed matter. In the early days of correlated electron physics models were most often phenomenologically motivated, without the ambition of a microscopic derivation, let alone a quantitative description. Within the last decade, however, a new research field has developed at the interface of many-body theory and first prinicples electronic structure calculations. The aim is the construction of materials-specific parameterfree many-body theories that preserve the ab initio nature of density functional based electronic structure calculations, but incorporate at the same time a many-body description of Coulomb interactions beyond the independent-electron picture into the description of spectroscopic or finite-temperature properties.