LDA+Gutzwiller Method for Correlated Electron Systems: Formalism and Its Applications

TL;DR

The paper introduces a new ab initio LDA+Gutzwiller method that combines Gutzwiller variational approach with DFT, providing accurate ground state calculations for correlated electron systems at lower computational cost than DMFT.

Contribution

It develops a Gutzwiller density functional theory (GDFT) integrating Gutzwiller approach with DFT, enabling efficient and accurate analysis of strongly correlated materials.

Findings

Comparable accuracy to DMFT for ground states

More computationally efficient than DMFT

Improved agreement with experimental results

Abstract

We introduce in detail our newly developed \textit{ab initio} LDA+Gutzwiller method, in which the Gutzwiller variational approach is naturally incorporated with the density functional theory (DFT) through the "Gutzwiller density functional theory (GDFT)" (which is a generalization of original Kohn-Sham formalism). This method can be used for ground state determination of electron systems ranging from weakly correlated metal to strongly correlated insulators with long-range ordering. We will show that its quality for ground state is as high as that by dynamic mean field theory (DMFT), and yet it is computationally much cheaper. In additions, the method is fully variational, the charge-density self-consistency can be naturally achieved, and the quantities, such as total energy, linear response, can be accurately obtained similar to LDA-type calculations. Applications on several typical systems are presented, and the characteristic aspects of this new method are clarified. The obtained results using LDA+Gutzwiller are in better agreement with existing experiments, suggesting significant improvements over LDA or LDA+U.