Electron-phonon interactions from Monte-Carlo sampling: Difference between revisions
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It also involves phonon calculations for the <math>\Gamma</math> point (see {{TAG|Phonons from finite differences}}). So many tags in the {{TAG|INCAR}} will be used from the phonon calculations. | It also involves phonon calculations for the <math>\Gamma</math> point (see {{TAG|Phonons from finite differences}}). So many tags in the {{TAG|INCAR}} will be used from the phonon calculations. | ||
To enable electron-phonon interactions from MC methods {{TAG|PHON_LMC}}=''.TRUE.'' has to be set in the {{TAG|INCAR}} file. Also {{TAG|IBRION}}=6 has to be selected (the MC method is currently only implemented for {{TAG|IBRION}}=6). | |||
To enable electron-phonon interactions from MC methods {{TAG|PHON_LMC}}=''.TRUE.'' has to be set in the {{TAG|INCAR}} file. | |||
== Full MC sampling == | == Full MC sampling == | ||
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System = DEFAULT | System = DEFAULT | ||
PREC = Accurate | {{TAGBL|PREC}} = Accurate | ||
ISMEAR = 0; SIGMA = 0.1; | {{TAGBL|ISMEAR}} = 0; {{TAGBL|SIGMA}} = 0.1; | ||
IBRION = 6 | {{TAGBL|IBRION}} = 6 | ||
PHON_LMC = .TRUE. | {{TAGBL|PHON_LMC}} = .TRUE. | ||
PHON_NSTRUCT = 100 | {{TAGBL|PHON_NSTRUCT}} = 100 | ||
{{TAGBL|TEBEG}} = 0.0 | |||
== ZG configuration (one-shot sampling) | == ZG configuration (one-shot sampling) | ||
A sample {{TAG|INCAR}} file for the | A sample {{TAG|INCAR}} file for the | ||
Revision as of 10:07, 9 April 2019
Important: This feature will be only available from VASP6.0 or higher.
First of all this method needs a sufficiently large super cell. It also involves phonon calculations for the point (see Phonons from finite differences). So many tags in the INCAR will be used from the phonon calculations.
To enable electron-phonon interactions from MC methods PHON_LMC=.TRUE. has to be set in the INCAR file. Also IBRION=6 has to be selected (the MC method is currently only implemented for IBRION=6).
Full MC sampling
The tag PHON_NSTRUCT sets the number of structures generated due to the MC sampling. Convergence of the observable with respect to this number should be monitored.
The tag TEBEG=0 is also needed to choose the temperature at which the sampling is run.
Additionally the PHON_LBOSE can be set .TRUE. or .FALSE. (default PHON_LBOSE=.TRUE.), which selects Bose-Einstein or Maxwell-Boltzmann statistics, respectively.
A sample INCAR file for 0 K looks like the following:
System = DEFAULT PREC = Accurate ISMEAR = 0; SIGMA = 0.1; IBRION = 6 PHON_LMC = .TRUE. PHON_NSTRUCT = 100 TEBEG = 0.0
== ZG configuration (one-shot sampling)
A sample INCAR file for the