ABINIT Discussion Forums

Dear all

I need to study the convergence in energy cutoff (ecut) , lattice parameter (acell) and k-points and compute the band structure for GaN and AlN wurtzite phase.
but I can't build the corresponding input files. Especially for the wurtzite phase. I need some help to build these Input files.

Thank for advance

Regards

Bernard Naoussi

Can you be more specific? Do you at least have starting structures (.cif files or equivalent)?

Well, the tutorials explain in detail how to study convergence and optimize structures, have you done the tutorial lessons? With all respect, you really need to post more specific questions, as you know there are many input variables for abinit and it's not clear what it is you are having trouble with.

What structure are you using? Do you have a .cif or related file of structural information?

Here's an input file for actual wurtzite (ZnS) to get you started.

ecut 15
pawecutdg 30

prtgeo 2

toldff 1.0D-6

acell 3.8227 3.8227 6.2607 angstrom
angdeg 90. 90. 120.
spgroup 186

kptopt 1
kptrlen 60

ntypat 2
znucl 30 16

natom 4
natrd 2
typat 1 2

xred
1/3 2/3 0
1/3 2/3 0.3748

nstep 50
iscf 17
diemac 2.4

The file I posted is for wurtzite, which is ZnS. For GaN in the wurtzite structure, you will have to modify acell and xred to match the GaN values, and znucl to match Ga and N.

see test V2/case 07. Surely you can be working some of this stuff out for yourself.

Look for the cif on http://www.crystallography.net - xred coords are at the end of the file

Alain

http://www.crystallography.net/cif/9/9011658.cif
http://www.crystallography.net/cif/9/9011657.cif

Cuivis dolori remedium est patientia

Thank Alain

The CIF files have the xred of Ga, Al and N but I need the xred oh GaN and AlN in wurtzite phase please.

If it's possible, send me the xred of GaN and AlN in wurtzite phase. I need also the syntax of "jdtset" variables to study de convergence of acell and ecut. "udtset" can compute only max 9 values.

Thank for advance.


Best Regards.

Bernard_naoussi@yahoo.fr

I give up

Happy New Year to all forum members

Dear Prof jzwanzig,
I need your assistance on correction to this input file for doped CaB6. i want to determined optimized lattice parameter and the structure of the doped system.


#Optimization of the lattice parameters
optcell 1
ionmov 3
ntime 10
dilatmx 1.5
ecutsm 0.5
ecut 35
nsym 0
occopt 1
mkmem 0
#Definition of the k-point grids
kptopt 1 # Option for the automatic generation of k points, taking
# into account the symmetry
nshiftk 1
shiftk 0.5 0.5 0.5
ngkpt 4 4 4
getwfk -1

chkprim 0

#Definition of the SCF procedure
#nstep 300
toldfe 1.0d-8
diemac 9.0


#COMMON INPUT DATA###########################################################
#alchemical input
npsp 3
ntypalch 1
mixalch 0.95 0.05
#
# CaB6 lattice structure
ntypat 2
znucl 5 20 56
natom 7
typat 1 2 2 2 2 2 2

#Definition of the unit cell
acell 3*7.6
#angdeg 90 90 90
#spgroup 221

# Atomic positions
xred 0.00 0.00 0.00 #Ca1
0.50 0.50 0.20 #B2
0.50 0.50 -0.20 #B2
0.50 0.20 0.50 #B2
0.50 -0.20 0.50 #B2
0.20 0.50 0.50 #B2
0.80 0.50 0.50 #B2


ixc 11
timopt 2


Thanks alot prof