ELPH SCATTERING APPROX - Revision history

Miranda.henrique at 13:25, 30 June 2025

2025-06-30T13:25:02Z

← Older revision		Revision as of 13:25, 30 June 2025
Line 29:		Line 29:
	:Applies an energy-projected weight scaled by mean-free path:		:Applies an energy-projected weight scaled by mean-free path:
	:<math>		:<math>
	w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\|\mathbf{v}_{n\mathbf{k}}\| ~~\cdot~~ \|\mathbf{v}_{n'\mathbf{k}'}\|}\right) ~~\cdot~~ \left\| \frac{\varepsilon_{n'\mathbf{k}'} - \mu}{\varepsilon_{n\mathbf{k}} - \mu} \right\|		w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\|\mathbf{v}_{n\mathbf{k}}\| \|\mathbf{v}_{n'\mathbf{k}'}\|}\right) \left\| \frac{\varepsilon_{n'\mathbf{k}'} - \mu}{\varepsilon_{n\mathbf{k}} - \mu} \right\|
	</math>		</math>
			<!--
			{{NB\|warning\|As of vasp 6.5.1 this approximation is wrongly implemented. It should be
			:<math>
			w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\|\mathbf{v}_{n\mathbf{k}}\| \|\mathbf{v}_{n'\mathbf{k}'}\|} \cdot \left\| \frac{\varepsilon_{n'\mathbf{k}'} - \mu}{\varepsilon_{n\mathbf{k}} - \mu} \right\|\right)
			</math>
			}}-->
	;{{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\|ERTA_TAU }} - <u>E</u>nergy <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (lifetime approximation)
	:<math>		:<math>
	w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\|\mathbf{v}_{n\mathbf{k}}\|^2}\right) \cdot \left\| \frac{\varepsilon_{n'\mathbf{k}'} - \mu}{\varepsilon_{n\mathbf{k}} - \mu} \right\|		w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\|\mathbf{v}_{n\mathbf{k}}\|^2}\right) \left\| \frac{\varepsilon_{n'\mathbf{k}'} - \mu}{\varepsilon_{n\mathbf{k}} - \mu} \right\|
			</math>
			<!--
			{{NB\|warning\|As of vasp 6.5.1 this approximation is wrongly implemented. It should be
			:<math>
			w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\|\mathbf{v}_{n\mathbf{k}}\|^2} \left\| \frac{\varepsilon_{n'\mathbf{k}'} - \mu}{\varepsilon_{n\mathbf{k}} - \mu} \right\|\right)
	</math>		</math>
			}}-->
	;{{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_LAMDBA}} - <u>M</u>omentum <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (mean-free path approximation)
	:<math>		:<math>
	w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\|\mathbf{v}_{n\mathbf{k}}\| ~~\cdot~~ \|\mathbf{v}_{n'\mathbf{k}'}\|}\right)		w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\|\mathbf{v}_{n\mathbf{k}}\| \|\mathbf{v}_{n'\mathbf{k}'}\|}\right)
	</math>		</math>

Miranda.henrique at 13:14, 30 June 2025

2025-06-30T13:14:23Z

← Older revision		Revision as of 13:14, 30 June 2025
Line 17:		Line 17:

	;{{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		;{{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.		:Computes the relaxation time from the imaginary part of the Fan self-energy, evaluated on the electronic eigenenergy:
			:<math>
			\frac{1}{\tau^{\mathrm{SERTA}}_{n\mathbf{k}}} = \frac{2\pi}{\hbar} \sum_{n'\nu\mathbf{k}'} w_{n\mathbf{k},n'\mathbf{k}'} \, \|g^{\nu}_{n\mathbf{k},n'\mathbf{k}'}\|^2 \left[ (n_{\nu\mathbf{q}} + 1 - f_{n'\mathbf{k}'}) \, \delta(\varepsilon_{n\mathbf{k}} - \varepsilon_{n'\mathbf{k}'} - \hbar\omega_{\nu\mathbf{q}}) + (n_{\nu\mathbf{q}} + f_{n'\mathbf{k}'}) \, \delta(\varepsilon_{n\mathbf{k}} - \varepsilon_{n'\mathbf{k}'} + \hbar\omega_{\nu\mathbf{q}}) \right]
			</math>
			:Here, the scattering weight is:
			:<math>
			w_{n\mathbf{k},n'\mathbf{k}'} = 1
			</math>

	;{{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_LAMDBA}} - <u>E</u>nergy <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (mean-free path approximation)
			:Applies an energy-projected weight scaled by mean-free path:
	:<math>		:<math>
	w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\\|\mathbf{v}_{n\mathbf{k}}\\| \cdot \\|\mathbf{v}_{n'\mathbf{k}'}\\|}\right) \cdot \left\| \frac{\varepsilon_{n'\mathbf{k}'} - \~~varepsilon_F~~}{\~~hbar~~\~~omega~~ - \~~varepsilon_F~~} \right\|		w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\|\mathbf{v}_{n\mathbf{k}}\| \cdot \|\mathbf{v}_{n'\mathbf{k}'}\|}\right) \cdot \left\| \frac{\varepsilon_{n'\mathbf{k}'} - \mu}{\varepsilon_{n\mathbf{k}} - \mu} \right\|
	</math>		</math>

	;{{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\|ERTA_TAU }} - <u>E</u>nergy <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (lifetime approximation)
	:<math>		:<math>
	w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\\|\mathbf{v}_{n\mathbf{k}}\\|^2}\right) \cdot \left\| \frac{\varepsilon_{n'\mathbf{k}'} - \~~varepsilon_F~~}{\~~hbar~~\~~omega~~ - \~~varepsilon_F~~} \right\|		w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\|\mathbf{v}_{n\mathbf{k}}\|^2}\right) \cdot \left\| \frac{\varepsilon_{n'\mathbf{k}'} - \mu}{\varepsilon_{n\mathbf{k}} - \mu} \right\|
	</math>		</math>

	;{{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_LAMDBA}} - <u>M</u>omentum <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (mean-free path approximation)
	:<math>		:<math>
	w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\\|\mathbf{v}_{n\mathbf{k}}\\| \cdot \\|\mathbf{v}_{n'\mathbf{k}'}\\|}\right)		w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\|\mathbf{v}_{n\mathbf{k}}\| \cdot \|\mathbf{v}_{n'\mathbf{k}'}\|}\right)
	</math>		</math>

	;{{TAGO\|ELPH_SCATTERING_APPROX\|MRTA_TAU }} - <u>M</u>omentum <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (lifetime 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)
	:<math>		:<math>
	w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\\|\mathbf{v}_{n\mathbf{k}}\\|^2}\right)		w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\|\mathbf{v}_{n\mathbf{k}}\|^2}\right)
	</math>		</math>

Miranda.henrique at 12:56, 30 June 2025

2025-06-30T12:56:18Z

← Older revision		Revision as of 12:56, 30 June 2025
Line 19:		Line 19:
	:Calculates the relaxation time from the imaginary part of the electron self-energy.		: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_LAMDBA}} - <u>E</u>nergy <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (mean-free path approximation)
			:<math>
			w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\\|\mathbf{v}_{n\mathbf{k}}\\| \cdot \\|\mathbf{v}_{n'\mathbf{k}'}\\|}\right) \cdot \left\| \frac{\varepsilon_{n'\mathbf{k}'} - \varepsilon_F}{\hbar\omega - \varepsilon_F} \right\|
			</math>

	;{{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\|ERTA_TAU }} - <u>E</u>nergy <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (lifetime approximation)
			:<math>
			w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\\|\mathbf{v}_{n\mathbf{k}}\\|^2}\right) \cdot \left\| \frac{\varepsilon_{n'\mathbf{k}'} - \varepsilon_F}{\hbar\omega - \varepsilon_F} \right\|
			</math>

	;{{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_LAMDBA}} - <u>M</u>omentum <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (mean-free path approximation)
			:<math>
			w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\\|\mathbf{v}_{n\mathbf{k}}\\| \cdot \\|\mathbf{v}_{n'\mathbf{k}'}\\|}\right)
			</math>

	;{{TAGO\|ELPH_SCATTERING_APPROX\|MRTA_TAU }} - <u>M</u>omentum <u>R</u>elaxation-<u>T</u>ime <u>A</u>pproximation (lifetime 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)
			:<math>
			w_{n\mathbf{k},n'\mathbf{k}'} = \left(1 - \frac{\mathbf{v}_{n\mathbf{k}} \cdot \mathbf{v}_{n'\mathbf{k}'}}{\\|\mathbf{v}_{n\mathbf{k}}\\|^2}\right)
			</math>

	==Related tags and articles==		==Related tags and articles==

Mani: Add accumulator links

2025-02-28T08:47:37Z

Add accumulator links

← Older revision		Revision as of 08:47, 28 February 2025
Line 6:		Line 6:

	----		----
	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 ==
Line 22:		Line 25:
	==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]]

Mani: Add availability notice

2025-01-17T14:24:07Z

Add availability notice

← Older revision		Revision as of 14:24, 17 January 2025
Line 3:		Line 3:

	Description: Select which type of approximation is used to compute the electron scattering lifetimes due to electron-phonon coupling		Description: Select which type of approximation is used to compute the electron scattering lifetimes due to electron-phonon coupling
			{{Available\|6.5.0}}

	----		----

Mani: Improve page and add categories, related info

2024-12-19T17:05:44Z

Improve page and add categories, related info

← Older revision		Revision as of 17:05, 19 December 2024
Line 8:		Line 8:

	== Options to select ==		== 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.~~

Mani: Remove elph release banner

2024-12-18T14:24:17Z

Remove elph release banner

← Older revision		Revision as of 14:24, 18 December 2024
Line 1:		Line 1:
	~~{{elph_release}}~~
	{{DISPLAYTITLE:ELPH_SCATTERING_APPROX}}		{{DISPLAYTITLE:ELPH_SCATTERING_APPROX}}
	{{TAGDEF\|ELPH_SCATTERING_APPROX\|[string]\| SERTA MRTA_LAMBDA}}		{{TAGDEF\|ELPH_SCATTERING_APPROX\|[string]\| SERTA MRTA_LAMBDA}}

Miranda.henrique at 09:02, 8 October 2024

2024-10-08T09:02:44Z

← Older revision		Revision as of 09:02, 8 October 2024
Line 6:		Line 6:

	----		----
			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 possible options are:~~		== Options to select ==

	=== CRTA ===		=== CRTA ===
	Constant relaxation time approximation		Constant relaxation time approximation

Miranda.henrique at 08:56, 8 October 2024

2024-10-08T08:56:50Z

← Older revision		Revision as of 08:56, 8 October 2024
Line 3:		Line 3:
	{{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

	----		----

Miranda.henrique at 08:56, 8 October 2024

2024-10-08T08:56:21Z

@@ Line 1: / Line 1: @@
 {{elph_release}}
 {{DISPLAYTITLE:ELPH_SCATTERING_APPROX}}
-{{TAGDEF|ELPH_SCATTERING_APPROX|[string]| SERTA MRTA_LAMBDA
+{{TAGDEF|ELPH_SCATTERING_APPROX|[string]| SERTA MRTA_LAMBDA}}
-CRTA - constant relaxation time approximation
+----
-SERTA - self-energy relaxation time approximation