Yambo Community Forum

Posted: **Mon Jun 03, 2024 11:33 am**

Dear experts,
I have been trying to calculate average electron/hole density for a 2D heterostructure using the following ypp files:
for hole

Code: Select all

excitons                         # [R] Excitonic properties
avehole                          # [R] Average hole/electron wavefunction
wavefunction                     # [R] Wavefunction
Format= "c"                      # Output format [(c)ube/(g)nuplot/(x)crysden]
Direction= "123"                   # [rlu] [1/2/3] for 1d or [12/13/23] for 2d [123] for 3D
FFTGvecs=  80              Ry    # [FFT] Plane-waves
States= "36 - 36"                  # Index of the BS state(s)
BSQindex= 1                      # Q-Index of the BS state(s)
Degen_Step= 0.010000       eV    # Maximum energy separation of two degenerate states
EHdensity= "h"                   # Calculate (h)ole/(e)lectron density from BSE wave-function

for electron

Code: Select all

excitons                         # [R] Excitonic properties
avehole                          # [R] Average hole/electron wavefunction
wavefunction                     # [R] Wavefunction
Format= "c"                      # Output format [(c)ube/(g)nuplot/(x)crysden]
Direction= "123"                   # [rlu] [1/2/3] for 1d or [12/13/23] for 2d [123] for 3D
FFTGvecs=  80              Ry    # [FFT] Plane-waves
States= "36 - 36"                  # Index of the BS state(s)
BSQindex= 1                      # Q-Index of the BS state(s)
Degen_Step= 0.010000       eV    # Maximum energy separation of two degenerate states
EHdensity= "e"                   # Calculate (h)ole/(e)lectron density from BSE wave-function

However, when I open the cube files in vesta, I get the spatial distribution of positive charge only (image attached).
Can you point out what am I missing here?

Posted: **Tue Jun 04, 2024 7:46 am**

Dear Dhanjit,
the average electron/hole densities are defined as:

and they are both positive-definite. Of course nothing prevent you to change the sign of one of the two if this is what you need for plotting purpose.

Best,
Daniele

Posted: **Tue Jun 04, 2024 9:20 am**

Dear Daniele,
Thank you for your swift reply.
Now it's clear to me. I thought I missed something in the input file, as both electron/holes cube files were showing positive isosurface.

Yambo Community Forum

Electron/hole average density

Electron/hole average density

Re: Electron/hole average density

Re: Electron/hole average density