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O: Fachverband Oberflächenphysik
O 57: New Methods: Theory
O 57.1: Vortrag
Mittwoch, 20. März 2024, 16:15–16:30, MA 043
Periodic coupled-cluster theory for the ground and excited states with atom-centered basis functions — •Evgeny Moerman1, Felix Hummel2, Andreas Irmler2, Alejandro Gallo2, Andreas Grüneis2, and Matthias Scheffler1 — 1The NOMAD Laboratory at the FHI-MPG, Berlin — 2Inst. for Th. Phys., TU Wien, Vienna
Periodic coupled-cluster (CC) theory promises to be a reliable, highly accurate electronic structure method in materials science [1]. The all-electron code FHI-aims [2], which employs numeric atom-centered orbitals (NAOs), has been interfaced to the Cc4s code [3,4], making CC theory for both the ground and excited states accessible to FHI-aims. For molecules, the equation-of-motion-CC (EOM-CC) method predicts quasi-particle energies more accurately than the GW approximation[5], and we expect that this will also hold for bandstructures of solids. Like most correlated wave function methods, CC methods exhibit excessively slow convergence with the size of the super cell. So far, no efficient approach to address this problem exists for NAOs. We present the current state of the CC theory framework available in FHI-aims and possible avenues to address the finite-size error.
[1] G. Booth et al., Nature, 493, 365-370 (2013)
[2] The FHI-aims web page, https://fhi-aims.org
[3] F. Hummel et al., JCP, 146, 124105 (2017)
[4] E. Moerman et al., JOSS, 7, 4 (2022)
[5] M. Lange et al.,JCTC, 14, 4224-4236 (2018)
Keywords: electronic correlation; wave function theory; coupled-cluster theory; electronic band structure; finite-size effects