ELPH SCATTERING APPROX: Difference between revisions

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There are different approximations to compute the electronic lifetimes due to electron-phonon scattering. Each of these can lead to significantly different transport coefficients.
There are different approximations to compute the electronic lifetimes due to electron-phonon scattering.
Each of these can lead to significantly different transport coefficients.
It is possible to select more than one approximation in {{TAG|ELPH_SCATTERING_APPROX}}.
In this case, additional [[Electron-phonon accumulators | electron-phonon accumulators]] are created for each scattering approximation.


== Options to select ==
== Options to select ==
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==Related tags and articles==
==Related tags and articles==
* [[Transport coefficients including electron-phonon scattering|Transport calculations]]
* [[Transport coefficients including electron-phonon scattering|Transport calculations]]
* [[Electron-phonon accumulators]]
* {{TAG|ELPH_RUN}}
* {{TAG|ELPH_RUN}}
* {{TAG|TRANSPORT_RELAXATION_TIME}}
* {{TAG|TRANSPORT_RELAXATION_TIME}}


[[Category:INCAR tag]][[Category:Electron-phonon_interactions]]
[[Category:INCAR tag]][[Category:Electron-phonon_interactions]]

Latest revision as of 08:47, 28 February 2025

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

Mind: Available as of VASP 6.5.0

There are different approximations to compute the electronic lifetimes due to electron-phonon scattering. Each of these can lead to significantly different transport coefficients. It is possible to select more than one approximation in ELPH_SCATTERING_APPROX. In this case, additional electron-phonon accumulators are created for each scattering approximation.

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)

Related tags and articles