Performance of periodic EOM-CCSD for band gaps of inorganic semiconductors and insulators

TL;DR

This study evaluates the accuracy of periodic EOM-CCSD in predicting band gaps of inorganic semiconductors and insulators, analyzing convergence and comparing with EOM-MP2, with results close to experimental values.

Contribution

It demonstrates the effectiveness of periodic EOM-CCSD for band gap calculations and compares its performance with the more affordable EOM-MP2 method.

Findings

EOM-CCSD has a mean absolute error of 0.42 eV after corrections.

EOM-MP2 performs comparably to EOM-CCSD in this context.

Largest errors are observed for C, BP, and LiH.

Abstract

We calculate the band gaps of 12 inorganic semiconductors and insulators composed of atoms from the first three rows of the periodic table using periodic equation-of-motion coupled-cluster theory with single and double excitations (EOM-CCSD). Our calculations are performed with atom-centered triple-zeta basis sets and up to 64 $k$-points in the Brillouin zone. We analyze the convergence behavior with respect to number of orbitals and number of $k$-points sampled, using composite corrections and extrapolations to produce our final values. When accounting for electron-phonon corrections to experimental band gaps, we find that EOM-CCSD has a mean signed error of $-0.12$ eV and a mean absolute error of $0.42$ eV; the largest outliers are C (error of $-0.93$ eV), BP ($-1.00$ eV), and LiH ($+0.78$ eV). Surprisingly, we find that the more affordable partitioned EOM-MP2 theory performs as well as EOM-CCSD.