Deriving \textit{ab initio} model Hamiltonians for molecular crystals

TL;DR

This paper discusses the construction of extit{ab initio} model Hamiltonians for organic molecular crystals using Wannier orbitals, enabling more accurate electronic property modeling from first principles.

Contribution

It explains the methodology of extit{ab initio} model construction for molecular crystals and highlights its advantages over fitted models.

Findings

First principles models can yield significantly different results than fitted models.

Wannier orbitals are particularly well suited for molecular crystal modeling.

The approach improves understanding of strongly correlated phases.

Abstract

Developing realistic and precise models of the electronic properties of organic molecular crystals is crucial for understanding the full range of strongly correlated phases that they exhibit. By using \textit{ab initio} model construction methods, one can obtain unbiased non-interacting models of such systems from density functional theory, upon which one can base further (many-body) models. We will discuss the utility and advantages of \textit{ab initio} model construction using Wannier orbitals. We will briefly review the approach, and then explain why it is so well suited to molecular crystals in particular. We discuss the \textit{ab initio} construction of both non-interacting and interacting Hamitonians, and highlight recent examples where such first principles models lead to importantly different results than fitted models.