ELPH SCATTERING APPROX: Difference between revisions

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)

@@ Line 8: / Line 8: @@
 == Options to select ==
-=== CRTA ===
+;{{TAGO|ELPH_SCATTERING_APPROX|CRTA}} - <u>C</u>onstant <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation
-Constant relaxation time approximation
+: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.}}
-=== SERTA ===
+;{{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
-Self-energy relaxation time approximation
+: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)
-=== ERTA_LAMDBA ===
+==Related tags and articles==
-Energy relaxation time approximation (mean-free path approximation)
+* [[Transport coefficients including electron-phonon scattering|Transport calculations]]
+* {{TAG|ELPH_RUN}}
+* {{TAG|TRANSPORT_RELAXATION_TIME}}
-=== ERTA_TAU ===
+[[Category:INCAR tag]][[Category:Electron-phonon_interactions]]
-Energy relaxation time approximation (lifetime approximation)
-=== MRTA_LAMDBA ===
-Momentum relaxation time approximation (mean-free path approximation)
-=== MRTA_TAU ===
-Momentum relaxation time approximation (lifetime approximation)
-Note that when the CRTA option is selected, the reading of the {{FILE|phelel_params.hdf5}} file and calculation of electron self-energy is completely skipped.