Model Hamiltonian for strongly-correlated systems: Systematic, self-consistent, and unique construction

TL;DR

This paper introduces a rigorous, self-consistent method to couple strongly-correlated lattice models with density functional theory, enabling accurate ab initio calculations of geometric and topological properties without energy scale separation.

Contribution

It presents a systematic, self-consistent framework for constructing a unique model Hamiltonian for strongly-correlated systems integrated with DFT.

Findings

Accurately reproduces many-body polarization in Hubbard models.

Provides a self-consistent approach to incorporate momentum-dependent correlations.

Enables ab initio calculations of geometric and topological properties.

Abstract

An interacting lattice model describing the subspace spanned by a set of strongly-correlated bands is rigorously coupled to density functional theory to enable ab initio calculations of geometric and topological material properties. The strongly-correlated subspace is identified from the occupation number band structure as opposed to a mean-field energy band structure. The self-consistent solution of the many-body model Hamiltonian and a generalized Kohn-Sham equation exactly incorporates momentum-dependent and crystal-symmetric correlations into electronic structure calculations in a way that does not rely on a separation of energy scales. Calculations for a multiorbital Hubbard model demonstrate that the theory accurately reproduces the many-body polarization.