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

A versatile method for combining density functional theory in the local density approximation 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 and the $N\text{th}$ order muffin-tin-orbital methods. Two correlated materials with different degrees of structural and electronic complexity, $\mathrm{Sr}\mathrm{V}{\mathrm{O}}_3$ and $\mathrm{Ba}\mathrm{V}{\mathrm{S}}_3$, are investigated as case studies. $\mathrm{Sr}\mathrm{V}{\mathrm{O}}_3$ 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 $\mathrm{Ba}\mathrm{V}{\mathrm{S}}_3$ is known for its rich and complex physics, associated with strong correlation effects and low-dimensional characteristics. 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.