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We demonstrate that coupled-cluster singles-and-doubles Greens function (GFCCSD) method is a powerful and prominent tool drawing the electronic band structures and the total energies, which many theoretical techniques struggle to reproduce. We have calculated single-electron energy spectra via GFCCSD method for various kinds of systems, ranging from ionic to covalent and van der Waals, for the first time: one-dimensional LiH chain, one-dimensional C chain, and one-dimensional Be chain. We have found that the band gap becomes narrower than in HF due to the correlation effect. We also show that the band structures obtained from GFCCSD method include both quasiparticle and satellite peaks successfully. Besides, taking one-dimensional LiH as an example, we discuss the validity of restricting the active space to suppress the computational cost of GFCCSD method while maintaining the accuracy. We show that the calculated results without bands that do not contribute to the chemical bonds are in good agreement with full-band calculations. With GFCCSD method, we can calculate the total energy and band structures with high precision.
In this study, we have calculated single-electron energy spectra via the Greens function based on the coupled-cluster singles and doubles (GFCCSD) method for isolated atoms from H to Ne. In order to check the accuracy of the GFCCSD method, we compare
Coupled cluster Greens function (CCGF) approach has drawn much attention in recent years for targeting the molecular and material electronic structure problems from a many-body perspective in a systematically improvable way. Here, we will present a b
Within the self-energy embedding theory (SEET) framework, we study coupled cluster Greens function (GFCC) method in two different contexts: as a method to treat either the system or environment present in the embedding construction. Our study reveals
We use an analytical model to describe the magnetocrystalline anisotropy energy (MAE) in solids as a function of band filling. The MAE is evaluated in second-order perturbation theory, which makes it possible to decompose the MAE into a sum of transi
We investigate the performance of Greens function coupled cluster singles and doubles (CCSD) method as a solver for Greens function embedding methods. To develop an efficient CC solver, we construct the one-particle Greens function from the coupled c