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Improved local-field corrections to the G_ {0} W approximation in jellium: Importance of consistency relations

Almbladh, Carl-Olof LU and Hindgren, Mikael (1997) In Physical Review B 56(20). p.12832-12839
Abstract
We study the effects of local vertex corrections to the self-energy of the electron gas. We find that a vertex derived from time-dependent density-functional theory can give accurate self-energies, provided, however, a proper decay at large momentum transfer (large q) is built into the vertex function. (The local-density approximation for the vertex fails badly.) Total energies are calculated from the Galitskii-Migdal formula, and it is shown that a proper large-q behavior results in a close consistency between the chemical potentials derived from these energies and those obtained directly from the self-energy. We show that this internal consistency depends critically on including the same vertex correction in both the self-energy and the... (More)
We study the effects of local vertex corrections to the self-energy of the electron gas. We find that a vertex derived from time-dependent density-functional theory can give accurate self-energies, provided, however, a proper decay at large momentum transfer (large q) is built into the vertex function. (The local-density approximation for the vertex fails badly.) Total energies are calculated from the Galitskii-Migdal formula, and it is shown that a proper large-q behavior results in a close consistency between the chemical potentials derived from these energies and those obtained directly from the self-energy. We show that this internal consistency depends critically on including the same vertex correction in both the self-energy and the screening function. In addition the total energies become almost as accurate as those from elaborate Monte Carlo calculations. This as well as previous works show that self-energy corrections are important for properly describing electron propagation at energies around and above the plasmon energy. For easy use in calculations of photoemission and x-ray extended fine structure spectra, we parametrize our calculated self-energies in terms of a simple analytical expression. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B
volume
56
issue
20
pages
12832 - 12839
publisher
American Physical Society
ISSN
1550-235X
language
English
LU publication?
yes
id
bf22f475-bf47-4d5a-b007-506bb15c9593 (old id 8774182)
date added to LUP
2016-02-27 01:00:17
date last changed
2018-10-03 12:07:23
@article{bf22f475-bf47-4d5a-b007-506bb15c9593,
  abstract     = {We study the effects of local vertex corrections to the self-energy of the electron gas. We find that a vertex derived from time-dependent density-functional theory can give accurate self-energies, provided, however, a proper decay at large momentum transfer (large q) is built into the vertex function. (The local-density approximation for the vertex fails badly.) Total energies are calculated from the Galitskii-Migdal formula, and it is shown that a proper large-q behavior results in a close consistency between the chemical potentials derived from these energies and those obtained directly from the self-energy. We show that this internal consistency depends critically on including the same vertex correction in both the self-energy and the screening function. In addition the total energies become almost as accurate as those from elaborate Monte Carlo calculations. This as well as previous works show that self-energy corrections are important for properly describing electron propagation at energies around and above the plasmon energy. For easy use in calculations of photoemission and x-ray extended fine structure spectra, we parametrize our calculated self-energies in terms of a simple analytical expression.},
  author       = {Almbladh, Carl-Olof and Hindgren, Mikael},
  issn         = {1550-235X},
  language     = {eng},
  number       = {20},
  pages        = {12832--12839},
  publisher    = {American Physical Society},
  series       = {Physical Review B},
  title        = {Improved local-field corrections to the G_ {0} W approximation in jellium: Importance of consistency relations},
  volume       = {56},
  year         = {1997},
}