Second-order dual fermion for multi-orbital systems

Erik G C P van Loon

doi:10.1088/1361-648X/abd9ed

Second-order dual fermion for multi-orbital systems

J Phys Condens Matter. 2021 Jan 25;33(13). doi: 10.1088/1361-648X/abd9ed.

Author

Erik G C P van Loon¹

Affiliation

¹ Institute for Theoretical Physics and Bremen Center For Computational Materials Science, University of Bremen, Bremen, Germany.

PMID: 33418544
DOI: 10.1088/1361-648X/abd9ed

Abstract

In dynamical mean-field theory, the correlations between electrons are assumed to be purely local. The dual fermion approach provides a systematic way of adding non-local corrections to the dynamical mean-field theory starting point. Initial applications of this method were largely restricted to the single-orbital Hubbard model. Here, we present an implementation of second-order dual fermion for general multi-orbital systems and use this approach to investigate spatial correlations in SrVO₃. In addition, the approach is benchmarked in several exactly solvable small systems.

Keywords: dual fermion; spatial correlations; strongly correlated electrons.