Preprint article · Journal article
Beyond the RPA and GW methods with adiabatic xc-kernels for accurate ground state and quasiparticle energies
Computational Atomic-scale Materials Design, Department of Physics, Technical University of Denmark1
Department of Physics, Technical University of Denmark2
Center for Nanostructured Graphene, Centers, Technical University of Denmark3
University of Warwick4
Appalachian State University5
Temple University6
We review the theory and application of adiabatic exchange–correlation (xc)-kernels for ab initio calculations of ground state energies and quasiparticle excitations within the frameworks of the adiabatic connection fluctuation dissipation theorem and Hedin’s equations, respectively. Various different xc kernels, which are all rooted in the homogeneous electron gas, are introduced but hereafter we focus on the specific class of renormalized adiabatic kernels, in particular the rALDA and rAPBE.
The kernels drastically improve the description of short-range correlations as compared to the random phase approximation (RPA), resulting in significantly better correlation energies. This effect greatly reduces the reliance on error cancellations, which is essential in RPA, and systematically improves covalent bond energies while preserving the good performance of the RPA for dispersive interactions.
For quasiparticle energies, the xc-kernels account for vertex corrections that are missing in the GW self energy. In this context, we show that the short-range correlations mainly correct the absolute band positions while the band gap is less affected in agreement with the known good performance of GW for the latter.
The renormalized xc kernels offer a rigorous extension of the RPA and GW methods with clear improvements in terms of accuracy at little extra computational cost.
Language: | English |
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Publisher: | Nature Publishing Group UK |
Year: | 2019 |
Pages: | 53 |
ISSN: | 20573960 |
Types: | Preprint article and Journal article |
DOI: | 10.1038/s41524-019-0242-8 |
ORCIDs: | Olsen, Thomas , 0000-0002-1843-1269 , 0000-0002-2520-9594 and Thygesen, Kristian Sommer |