As an important technique to study the interaction between light and matter, optical absorption spectroscopy has been widely used in the areas of photovoltaics, photocatalysis, light-emitting diodes, and many more. The ability to compute optical absorption spectra from first principles is of great importance both to complement experiments and to predict the properties of new materials. On the other hand, recent years have seen the rapid development of wavefunction-based quantum chemistry methods with periodic boundary conditions, where accurate predictions on various electronic properties have been shown for periodic solids. Here, we present ab initio optical absorption spectra for a variety of semiconductors and insulators with Gaussian-based periodic equation-of-motion coupled-cluster theory with single and double excitations (EOM-CCSD). Our results have shown that the excitonic effects that dominate the low energy part of optical spectra for insulators and semiconductors are quantitatively described by EOM-CCSD. Comparison will be made to the Green’s function based GW/BSE results and experimental spectra. Detailed discussions on the basis-set dependence, finite-size effects, and various approximations will be provided.

Towards accurate prediction of optical absorption spectra for semiconductors and insulators with periodic coupled-cluster theory

ACS Spring Meeting 2021

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