Issue with electro-optic coefficient calculation

Running Abinit Response calculations
1

Hello,

ScAlN.abi (5.0 KB)

I’ve attached the input file I was using to try to calculate the piezoelectric and electro-optic coefficients for ScAlN. I used the structure.num_valence_electrons(pseudos=pseudos) function in abipy to get the number of valence electrons for setting the value of nband, and structure = Structure.from_mpid(“mp-1246075”) to get the structure of the molecule for the initial values of xred and rprim. The input file calculates through dataset 4 without issue. However, when I get to dataset 5, I get the following error:

— !ERROR
src_file: m_nonlinear.F90
src_line: 1549
mpi_rank: 0
message: |
In a non-linear response calculation, nband must be equal
to the number of valence bands.
…

Why would this error occur when nband is equal to the number of valence bands?

Thank you,

Joseph

2

Hi, I think your unit cell contains 96 electrons, but since you’re running it with occopt 1 (the default), you would have 96/2 = 48 bands (each band will be doubly occupied). Try it with nband 48.

3

I should have mentioned, you can check this by looking in the output file of your failed run, and examine the variable “occ”, which I suspect will show 48 2’s and 48 0’s, because I think you are running with 48 filled bands and 48 empty bands.

4

Thank you, this fixed it :slight_smile: