Dynamical mean-field theory using Wannier functions: a flexible route to electronic structure calculations of strongly correlated materials

TL;DR

This paper introduces a flexible method combining density functional theory and dynamical mean-field theory using Wannier functions, enabling detailed electronic structure calculations of strongly correlated materials with different complexities.

Contribution

It presents a general basis-independent framework utilizing Wannier functions to interface DFT and DMFT, comparing two Wannier schemes and applying them to complex materials.

Findings

Applied to SrVO3 and BaVS3, revealing correlation effects on Fermi surfaces.

Compared MLWF and NMTO Wannier schemes for better interface with DMFT.

Provided formalism for self-consistent charge density calculations in Wannier basis.

Abstract

A versatile method for combining density functional theory (DFT) in the local density approximation (LDA) with dynamical mean-field theory (DMFT) is presented. Starting from a general basis-independent formulation, we use Wannier functions as an interface between the two theories. These functions are used for the physical purpose of identifying the correlated orbitals in a specific material, and also for the more technical purpose of interfacing DMFT with different kinds of band-structure methods (with three different techniques being used in the present work). We explore and compare two distinct Wannier schemes, namely the maximally-localized-Wannier-function (MLWF) and the $N$-th order muffin-tin-orbital (NMTO) methods. Two correlated materials with different degrees of structural and electronic complexity, SrVO3 and BaVS3, are investigated as case studies. SrVO3 belongs to the canonical class of correlated transition-metal oxides, and is chosen here as a test case in view of its simple structure and physical properties. In contrast, the sulfide BaVS3 is known for its rich and complex physics, associated with strong correlation effects and low-dimensional characteristics. New insights into the physics associated with the metal-insulator transition of this compound are provided, particularly regarding correlation-induced modifications of its Fermi surface. Additionally, the necessary formalism for implementing self-consistency over the electronic charge density in a Wannier basis is discussed.