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]] | ||
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)