# Semilocal exchange-correlation potentials for solid-state calculations: Current status and future directions

## TL;DR

This paper reviews semilocal exchange-correlation potentials in Kohn-Sham DFT for solids, focusing on their current status, accuracy for properties like band gaps and magnetic moments, and future research directions.

## Contribution

It provides a comprehensive overview of semilocal xc methods, especially the modified Becke-Johnson potential, highlighting their applications and limitations in solid-state calculations.

## Key findings

- Modified Becke-Johnson potential effectively predicts band gaps.
- Semilocal methods enable large-scale solid-state simulations.
- Accuracy varies for properties like magnetic moments and electron density.

## Abstract

Kohn-Sham (KS) density functional theory (DFT) is a very efficient method for calculating various properties of solids as, for instance, the total energy, the electron density, or the electronic band structure. The KS-DFT method leads to rather fast calculations, however the accuracy depends crucially on the chosen approximation for the exchange and correlation (xc) functional $E_{\text{xc}}$ and/or potential $v_{\text{xc}}$. Here, an overview of xc methods to calculate the electronic band structure is given, with the focus on the so-called semilocal methods that are the fastest in KS-DFT and allow to treat systems containing up to thousands of atoms. Among them, there is the modified Becke-Johnson potential that is widely used to calculate the fundamental band gap of semiconductors and insulators. The accuracy for other properties like the magnetic moment or the electron density, that are also determined directly by $v_{\text{xc}}$, is also discussed.