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Hi All, I am trying to calculate piezoelectric tensor of tetragonal BaTiO3 with the help of VASP package program, I've written LEPSILON=T in INCAR file, after end of the job, I can get PIEZOELECTRIC TENSOR in the unit of C/m^2. It doesn't match with the literature works.

I obtained the elastic constants, and took the inverse of it via MATLAB for get to compliance tensor, then multiply the result with piezoelectric tensor that is coming from the VASP. What would be the possible reasons behind my miscalculation? 

Does anyone know that calculate piezoelectric constant at VASP program? Does not "LEPSILON=T" tag give to piezoelectric tensor in C/m^2 unit ?. Available from: https://www.researchgate.net/post/Does_ ... _C_m2_unit [accessed Mar 21, 2015].

Can you be more specific? Did you use LDA/GGA, what about k-points, +U, E-cutoff etc.?

What piezoelectric tensor did you obtain and what did the literature report?

Dear All,

Yes of course! I've used GGA approximation when I create the POTCAR file.
P.S: I've tried the others etc, PBE,LDA or LDA52, all answers were approximately same magnitude.

K-POINTS file=
8x8x8 Monkhorst-Pack k-point file
0
M
8 8 8
0. 0. 0.

INCAR file=
SYSTEM = BaTiO3
ISMEAR = -5
SIGMA = 0.05
###### Electronic Relaxation #########
ENCUT = 520
PREC = H
EDIFF = 1.E-04
##### Ionic Relaxation ########
ICHARG = 2
EDIFFG = -0.01
LREAL = A
LWAVE = F
LCHARG = T
LEPSILON = T


Is it more clearer now? Have you checked out my ResearchGate post? I had nightmare because of this problem please help!

Thanks!

As I mentioned before:

What piezoelectric tensor did you obtain and what did the literature report?