Charge self-consistency in density functional theory + dynamical mean field theory: k-space reoccupation and orbital order

TL;DR

This paper investigates how charge self-consistency in DFT+DMFT calculations causes k-space reoccupation and orbital order changes, revealing charge redistribution effects even with fixed Wannier orbital filling.

Contribution

It demonstrates the impact of charge self-consistency on k-space reoccupation and orbital polarization in DFT+DMFT, highlighting effects beyond simple charge transfer.

Findings

Charge redistribution occurs due to k-space reoccupation in DFT+DMFT.

Orbital polarization is enhanced by correlations in SrVO3.

Charge effects are significant even with fixed Wannier orbital filling.

Abstract

We study effects of charge self-consistency within the combination of density functional theory (DFT; Wien2k) with dynamical mean field theory (DMFT; w2dynamics) in a basis of maximally localized Wannier orbitals. Using the example of two cuprates, we demonstrate that even if there is only a single Wannier orbital with fixed filling, a noteworthy charge redistribution can occur. This effect stems from a reoccupation of the Wannier orbital in k-space when going from the single, metallic DFT band to the split, insulating Hubbard bands of DMFT. We analyze another charge self-consistency effect beyond moving charge from one site to another: the correlation-enhanced orbital polarization in a freestanding layer of SrVO3.