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Lattice parameters of ZnO

Posted: Wed Sep 19, 2007 3:00 am
by vaspman
Hello! Dear VASP users
I am a new VASP user. I finished all the practice example without problem. I did some structural relaxation calcilations for some materials without problem. Now I am doing calculations on ZnO to find the lattice parameters. I use LDA but the lattice parametrs are not good and specialy the convergence of K-points is bad. I tried to use MP k-points and Gama centered but on both cases the lattice parametrs are far away from the Expt.
I use hexagonal unit cell.
Here are my results

MP-mesh Energy a c
222 -11.494313 3.186 5.438
333 -20.090362 3.154 5.143
446 -16.183364 3.183 5.273
555 -15.958511 3.179 5.315
666 -14.480588 3.179 5.327
777 -16.260802 3.165 5.289
888 -15.58627 3.189 5.226

The Gama centered mesh
222 -10.859297 3.253 5.274
333 -20.090362 3.154 5.143
555 -15.958511 3.179 5.315
666 -16.043754 3.184 5.314
777 -16.260802 3.165 5.289
888 -14.64875 3.188 5.326
101010 -14.24037 3.180 5.333

Here is my INCAR file
SYSTEM = ZnO
Starting parameters for this run:
NWRITE = 2 write-flag
ISTART = 0 job : 0-new, 1-cont, 2-samecut
ICHARG = 0 charge: 0-wave, 1-file, 2-atom, >10-const
INIWAV = 1 electr: 0-lowe 1-rand 2-diag
IBRION = 2
NSW = 50 number of steps for IOM
Electronic Relaxation:
PREC = high low | medium | high
# ENCUT = 240 kinetic energy cutoff (eV)
ISPIN = 1

NELMDL = -7 number of delayed ELM steps
NELM = 101 number of ELM steps
EDIFF = 1E-03 energy stopping-criterion for ELM
EDIFFG = .1E-02 energy stopping-criterion for IOM
LREAL = .FALSE. real-space projection (.FALSE., .TRUE., On, Auto)
IALGO = 48 algorithm (8=CG for small, 48=RMM for big systems)

LCHARG = .T.
LWAVE = .FALSE.

ISIF = 3 (1:force=y stress=trace only ions=y shape=n volume=n)
ISYM = 1 (1-use symmetry, 0-no symmetry)

DOS related values:
ISMEAR = 0 (-5:tet_b,-4:tet,-3:scan,-1:Fermi,0:gaus,1:MP)
SIGMA = 0.1 broadening in eV

Here is my POSCAR file
Wurtzite
3.2495
1.0 0.0 0.0
0.0 1.0 0.0
0.0 0.0 1.6024
2 2
d
0.000 0.000 0.0
0.333 0.667 0.5
0.000 0.000 0.345
0.333 0.667 0.845

I will be very thankful if some one let me know how to solve this problem.
Thank you

Re: Lattice parameters of ZnO

Posted: Wed Sep 11, 2024 1:34 pm
by support_vasp

Hi,

We're sorry that we didn’t answer your question. This does not live up to the quality of support that we aim to provide. The team has since expanded. If we can still help with your problem, please ask again in a new post, linking to this one, and we will answer as quickly as possible.

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