Absorption Spectra of Solids from Periodic Equation-of-Motion Coupled-Cluster Theory

TL;DR

This paper demonstrates a method to compute the absorption spectra of solids using periodic EOM-CCSD, providing accurate spectral lineshapes and energy ranges, with some systematic energy shifts compared to experiments.

Contribution

It introduces an efficient Gaussian-based periodic EOM-CCSD approach for calculating solid-state absorption spectra without explicit excited state enumeration.

Findings

Spectra agree well with experimental lineshapes

Spectral energies are shifted by about 1 eV higher

Method efficiently covers tens of eV energy range

Abstract

We present ab initio absorption spectra of six three-dimensional semiconductors and insulators calculated using Gaussian-based periodic equation-of-motion coupled-cluster theory with single and double excitations (EOM-CCSD). The spectra are calculated efficiently by solving a system of linear equations at each frequency, giving access to an energy range of tens of eV without explicit enumeration of excited states. We assess the impact of Brillouin zone sampling, for which it is hard to achieve convergence due to the cost of EOM-CCSD. Although our most converged spectra exhibit lineshapes that are in good agreement with experiment, they are uniformly shifted to higher energies by about 1 eV. We tentatively attribute this discrepancy to a combination of vibrational effects and the remaining electron correlation, i.e., triple excitations and above.