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Ab initio study of the downfolded self-energy for correlated systems: Momentum dependence and effects of dynamical screening

Sakuma, Rei LU ; Martins, C.; Miyake, T. and Aryasetiawan, Ferdi LU (2014) In Physical Review B (Condensed Matter and Materials Physics) 89(23).
Abstract
The electronic structure of strongly correlated systems is usually calculated by using an effective model Hamiltonian with a small number of states and an effective on-site interaction. The mode, however, neglects the frequency dependence of the interaction, which emerges as a result of dynamical screening processes not included in the model. The self-energy calculated in this kind of model within dynamical mean-field theory (DMFT) is usually assumed to contain on-site components only. To study the validity of model calculations for the simulation of realistic materials, we make a detailed comparison between the downfolded self-energy in a model Hamiltonian with static and dynamic on-site interaction and the full ab initio self-energy for... (More)
The electronic structure of strongly correlated systems is usually calculated by using an effective model Hamiltonian with a small number of states and an effective on-site interaction. The mode, however, neglects the frequency dependence of the interaction, which emerges as a result of dynamical screening processes not included in the model. The self-energy calculated in this kind of model within dynamical mean-field theory (DMFT) is usually assumed to contain on-site components only. To study the validity of model calculations for the simulation of realistic materials, we make a detailed comparison between the downfolded self-energy in a model Hamiltonian with static and dynamic on-site interaction and the full ab initio self-energy for Fe and SrVO3 within the GW approximation. We find that the model GW self-energy shows weaker k (momentum) dependence than the ab initio GW self-energy, which is attributed to the lack of the long-range interaction and of contributions from other electrons not included in the models. This weak k dependence is found to lead to an artificial narrowing of the quasiparticle band structure. Moreover, this band narrowing is stronger for the dynamic (frequency-dependent) interaction, due to a larger renormalization of the quasiparticle states. These findings indicate a crucial role of the k dependence of the self-energy and dynamical screening for the electronic structure of correlated systems. We also discuss the effects beyond the GW approximation for correlated systems by comparing the GW and DMFT results. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B (Condensed Matter and Materials Physics)
volume
89
issue
23
publisher
American Physical Society
external identifiers
  • wos:000338510900001
  • scopus:84903582371
ISSN
1098-0121
DOI
10.1103/PhysRevB.89.235119
language
English
LU publication?
yes
id
0f6766da-c322-45ef-9f10-919b622562f1 (old id 4605775)
date added to LUP
2014-09-04 12:26:09
date last changed
2017-09-24 03:50:07
@article{0f6766da-c322-45ef-9f10-919b622562f1,
  abstract     = {The electronic structure of strongly correlated systems is usually calculated by using an effective model Hamiltonian with a small number of states and an effective on-site interaction. The mode, however, neglects the frequency dependence of the interaction, which emerges as a result of dynamical screening processes not included in the model. The self-energy calculated in this kind of model within dynamical mean-field theory (DMFT) is usually assumed to contain on-site components only. To study the validity of model calculations for the simulation of realistic materials, we make a detailed comparison between the downfolded self-energy in a model Hamiltonian with static and dynamic on-site interaction and the full ab initio self-energy for Fe and SrVO3 within the GW approximation. We find that the model GW self-energy shows weaker k (momentum) dependence than the ab initio GW self-energy, which is attributed to the lack of the long-range interaction and of contributions from other electrons not included in the models. This weak k dependence is found to lead to an artificial narrowing of the quasiparticle band structure. Moreover, this band narrowing is stronger for the dynamic (frequency-dependent) interaction, due to a larger renormalization of the quasiparticle states. These findings indicate a crucial role of the k dependence of the self-energy and dynamical screening for the electronic structure of correlated systems. We also discuss the effects beyond the GW approximation for correlated systems by comparing the GW and DMFT results.},
  articleno    = {235119},
  author       = {Sakuma, Rei and Martins, C. and Miyake, T. and Aryasetiawan, Ferdi},
  issn         = {1098-0121},
  language     = {eng},
  number       = {23},
  publisher    = {American Physical Society},
  series       = {Physical Review B (Condensed Matter and Materials Physics)},
  title        = {Ab initio study of the downfolded self-energy for correlated systems: Momentum dependence and effects of dynamical screening},
  url          = {http://dx.doi.org/10.1103/PhysRevB.89.235119},
  volume       = {89},
  year         = {2014},
}