Electronic Structure Calculation by First Principles for Strongly Correlated Electron Systems

TL;DR

This paper reviews recent advances in ab initio methods for strongly correlated electron systems, introducing a three-stage renormalized multi-scale solver that effectively models complex materials.

Contribution

It develops a hierarchical, ab initio downfolding scheme with low-energy solvers, advancing the computational study of strongly correlated materials.

Findings

The RMS method enables effective modeling of complex correlated materials.

Application examples include semiconductors, transition metals, and organic conductors.

The approach improves understanding of phenomena beyond single-particle theories.

Abstract

Recent trends of ab initio studies and progress in methodologies for electronic structure calculations of strongly correlated electron systems are discussed. The interest for developing efficient methods is motivated by recent discoveries and characterizations of strongly correlated electron materials and by requirements for understanding mechanisms of intriguing phenomena beyond a single-particle picture. A three-stage scheme is developed as renormalized multi-scale solvers (RMS) utilizing the hierarchical electronic structure in the energy space. It provides us with an ab initio downfolding of the global band structure into low-energy effective models followed by low-energy solvers for the models. The RMS method is illustrated with examples of several materials. In particular, we overview cases such as dynamics of semiconductors, transition metals and its compounds including iron-based superconductors and perovskite oxides, as well as organic conductors of kappa-ET type.