ELPH SELFEN CARRIER DEN RANGE: Difference between revisions

Latest revision as of 10:37, 21 October 2025

ELPH_SELFEN_CARRIER_DEN_RANGE = [real array]

Description: List of carrier density ranges in logarithmic scale (in [math]\displaystyle{ cm^{-3} }[/math]) at which to compute the phonon-mediated electron self-energy and transport coefficients.

   Warning: Not yet released!

This page contains information about a feature that will be available in a future release of VASP. In other words, currently you cannot use it even with the latest version of VASP. The information may change significantly until it is released.

From each carrier density specified in the array, a positive (electron doping) or negative (hole doping) number of electrons is added to the value of NELECT and the chemical potential computed. A range of carrier densities can be defined using ELPH_SELFEN_CARRIER_DEN_RANGE = l u n, where:

l is the lower limit of the carrier density range.
u is the upper limit of the carrier density range.
n is the number of steps between the two limits.

The range of carrier densities is used to generate a log-scale mesh of carrier densities.

Important: l or u must be both positive (n-doping) or both negative (p-doping).

You can add the range (l u n) N times, so you can have several different meshes of holes or electrons or both. For example, ELPH_SELFEN_CARRIER_DEN_RANGE = -1e20 -1e16 51 1e20 1e16 51 would create a list of two meshes of carrier densities, (-1e20 -1e16 51) and (1e20 1e16 51). The first mesh has 51 carrier densities of holes between -1e16 and -1e20; the second mesh has 51 carrier densities of electrons between 1e16 and 1e20. You could also include more meshes if you want. You can check the carriers that you have chosen in the OUTCAR file:

Chemical potential calculation:
===============================

elph_ismear=-24
elph_fermi_nedos=     501
elph_selfen_carrier_den=
 -0.100E+21
 -0.832E+20
 -0.692E+20
...
 -0.145E+17
 -0.120E+17
 -0.100E+17
  0.100E+21
  0.832E+20
  0.692E+20
...
  0.145E+17
  0.120E+17
  0.100E+17

@@ Line 2: / Line 2: @@
 {{TAGDEF|ELPH_SELFEN_CARRIER_DEN_RANGE|[real array]}}
-Description: List of the range of carrier density (in <math>cm^{-3}</math>) at which to compute the phonon-mediated electron self-energy and transport coefficients.
+Description: List of carrier density ranges in logarithmic scale (in <math>cm^{-3}</math>) at which to compute the phonon-mediated electron self-energy and transport coefficients.
 <!--{{Available|6.5.2}}-->
 {{not released}}
@@ Line 11: / Line 11: @@
 * ''u'' is the upper limit of the carrier density range.
 * ''n'' is the number of steps between the two limits.
-{{NB|important|When ''l'' or ''u'' must both be positive (electrons are added, i.e., ''n''-doping) or negative (electrons are removed from - holes are added to - the system, i.e., ''p''-doping).}}
+The range of carrier densities is used to generate a log-scale mesh of carrier densities.
+{{NB|important|''l'' or ''u'' must be both positive (''n''-doping) or both negative (''p''-doping).}}
 <!--This can be useful for producing contour plots, e.g., of the ZT figure of merit link to elph-part5 tutorial + add in the list of mu in the OUTCAR?-->
-You can add these set three (''l'' ''u'' ''n'') N times, so have several ranges of holes or electrons or both. For example, {{TAGO|ELPH_SELFEN_CARRIER_DEN_RANGE|-1e20 -1e16 51 1e20 1e16 51}} would create a list of two groups of carrier densities, (<code>-1e20 -1e16 51</code>) and (<code>1e20 1e16 51</code>). The first group has 51 different carrier densities of holes between <code>-1e16</code> and <code>-1e20</code>; the second group has 51 different carrier densities of electrons between <code>1e16</code> and <code>1e20</code>. You could also include more groups if you want. You can check the carriers that you have chosen in the {{FILE|OUTCAR}} file:
+You can add the range (''l'' ''u'' ''n'') N times, so you can have several different meshes of holes or electrons or both. For example, {{TAGO|ELPH_SELFEN_CARRIER_DEN_RANGE|-1e20 -1e16 51 1e20 1e16 51}} would create a list of two meshes of carrier densities, (<code>-1e20 -1e16 51</code>) and (<code>1e20 1e16 51</code>). The first mesh has <code>51</code> carrier densities of holes between <code>-1e16</code> and <code>-1e20</code>; the second mesh has <code>51</code> carrier densities of electrons between <code>1e16</code> and <code>1e20</code>. You could also include more meshes if you want. You can check the carriers that you have chosen in the {{FILE|OUTCAR}} file:
   Chemical potential calculation:
@@ Line 36: / Line 38: @@
 .120E+17
 .100E+17
-{{NB|warning|Be careful not to combine holes and electrons in the same group, as this will likely not create the set of density that you desire, e.g.: {{TAGO|ELPH_SELFEN_CARRIER_DEN_RANGE|-1e20 1e20 3}} creates the following carrier density:
- elph_selfen_carrier_den{{=}}
-  -0.100E+21
-  -0.100E+41
-  -0.100E+61
-}}
 ==Related tags and articles==
 * [[Transport coefficients including electron-phonon scattering|Transport calculations]]
 * [[Electron-phonon accumulators]]
+* [[Chemical potential in electron-phonon interactions]]
 * {{TAG|ELPH_RUN}}
 * {{TAG|ELPH_SELFEN_MU}}