ABINIT Discussion Forums

I tried the tutorial tffield_6.in and it worked fine.
So, I branched out and changed to the real system I was working on: 40 atoms, monoclinic, with 156 val. bands.
Miserable failure: it did the polarization calc fine, but then hung for hours after that.

So, I decided to break up the ttfield_6.in.
1. I did the polarization cal and it ran fine. I copied over the WFK and all other output files to a new dir.
2. Then, in the new dir,I made a new in-file that just did this:

getwfk 1
berryopt 4
efield 0.0001 0.0001 0.0001

Should have run, no?

No.
Here is the error I get:
initberry: Reduced electric field (ebar)
red_efieldbar(1:3) = 0.001172310 0.002030586 0.002419097

initberry: for direction 1, nkstr = 8, nstr = 64
initberry: for direction 2, nkstr = 8, nstr = 64
initberry: for direction 3, nkstr = 8, nstr = 64

initberry: COMMENT -
As a rough estimate,
to be below the critical field, the bandgap of your system
should be larger than 0.53 eV.


================================================================================

Computing the polarization (Berry phase) for reciprocal vector:
0.12500 0.00000 0.00000 (in reduced coordinates)
0.01066 -0.00000 0.00145 (in cartesian coordinates - atomic units)
Number of strings: 64
Number of k points in string: 8

--- !BUG
src_file: berryphase_new.F90
src_line: 937
mpi_rank: 0
message: |
For k-point # 1,
the determinant of the overlap matrix is found to be 0.
...


leave_new: decision taken to exit ...


Now, I do have a gap -- of 1.2 eV. so that's not the issue.

Can someone please help.
Tnx.
JB

Please read the netiquette and get back to us with many more details. Which version of abinit which system are you in reduced dimensions?

Basically it can not find a neighborhood of inequivalent kpoint neighbors to perform the berry phase strings. This used to happen if your cell is very anisotropic and the nearest k in one direction is further than the second or third neighbor in another direction.