ELPH SCATTERING APPROX: Difference between revisions
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{{DISPLAYTITLE:ELPH_SCATTERING_APPROX}} | {{DISPLAYTITLE:ELPH_SCATTERING_APPROX}} | ||
{{TAGDEF|ELPH_SCATTERING_APPROX|[string]| SERTA MRTA_LAMBDA}} | {{TAGDEF|ELPH_SCATTERING_APPROX|[string]| SERTA MRTA_LAMBDA}} | ||
Description: Select which type of approximation is used to compute the electron scattering due to electron-phonon coupling | Description: Select which type of approximation is used to compute the electron scattering lifetimes due to electron-phonon coupling | ||
---- | ---- | ||
There are different approximations to compute the electronic lifetimes due to electron-phonon scattering. Each of these can lead to significantly different transport coefficients. | |||
The | == Options to select == | ||
;{{TAGO|ELPH_SCATTERING_APPROX|CRTA}} - <u>C</u>onstant <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation | |||
:The relaxation time is assumed constant. It needs to be specified via {{TAG|TRANSPORT_RELAXATION_TIME}}. In this case, the computation of electron-phonon matrix elements is skipped entirely, which is a huge performance boost compared to the other relaxation-time approximations. | |||
{{NB|warning|While the CRTA can be a reasonable approximation for metals, it will generally fail for insulators.}} | |||
;{{TAGO|ELPH_SCATTERING_APPROX|SERTA}} - <u>S</u>elf-<u>E</u>nergy <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation | |||
:Calculates the relaxation time from the imaginary part of the electron self-energy. | |||
;{{TAGO|ELPH_SCATTERING_APPROX|ERTA_LAMDBA}} - <u>E</u>nergy <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (mean-free path approximation) | |||
;{{TAGO|ELPH_SCATTERING_APPROX|ERTA_TAU }} - <u>E</u>nergy <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (lifetime approximation) | |||
;{{TAGO|ELPH_SCATTERING_APPROX|MRTA_LAMDBA}} - <u>M</u>omentum <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (mean-free path approximation) | |||
;{{TAGO|ELPH_SCATTERING_APPROX|MRTA_TAU }} - <u>M</u>omentum <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (lifetime approximation) | |||
== | ==Related tags and articles== | ||
* [[Transport coefficients including electron-phonon scattering|Transport calculations]] | |||
* {{TAG|ELPH_RUN}} | |||
* {{TAG|TRANSPORT_RELAXATION_TIME}} | |||
[[Category:INCAR tag]][[Category:Electron-phonon_interactions]] | |||
Latest revision as of 17:05, 19 December 2024
ELPH_SCATTERING_APPROX = [string]
Default: ELPH_SCATTERING_APPROX = SERTA MRTA_LAMBDA
Description: Select which type of approximation is used to compute the electron scattering lifetimes due to electron-phonon coupling
There are different approximations to compute the electronic lifetimes due to electron-phonon scattering. Each of these can lead to significantly different transport coefficients.
Options to select
ELPH_SCATTERING_APPROX = CRTA- Constant Relaxation-Time Approximation- The relaxation time is assumed constant. It needs to be specified via TRANSPORT_RELAXATION_TIME. In this case, the computation of electron-phonon matrix elements is skipped entirely, which is a huge performance boost compared to the other relaxation-time approximations.
| Warning: While the CRTA can be a reasonable approximation for metals, it will generally fail for insulators. |
ELPH_SCATTERING_APPROX = SERTA- Self-Energy Relaxation-Time Approximation- Calculates the relaxation time from the imaginary part of the electron self-energy.
ELPH_SCATTERING_APPROX = ERTA_LAMDBA- Energy Relaxation-Time Approximation (mean-free path approximation)ELPH_SCATTERING_APPROX = ERTA_TAU- Energy Relaxation-Time Approximation (lifetime approximation)ELPH_SCATTERING_APPROX = MRTA_LAMDBA- Momentum Relaxation-Time Approximation (mean-free path approximation)ELPH_SCATTERING_APPROX = MRTA_TAU- Momentum Relaxation-Time Approximation (lifetime approximation)