I'm trying to perform an equation of state calculation for FeSi compound with the following input
Code: Select all
ndtset 8
getwfk -1
#Definition of the unit cell
acell1 3*0.938
acell2 3*0.954
acell3 3*0.960
acell4 3*0.968
acell5 3*0.974
acell6 3*0.981
acell7 3*0.987
acell8 3*0.993
rprim 8.507000000 0.000000000 0.000000000
0.000000000 8.507000000 0.000000000
0.000000000 0.000000000 8.507000000
#Definition of the atom types
ntypat 2 # There are two types of atom
znucl 26 14 # The keyword "znucl" refers to the atomic number of the
# possible type(s) of atom. The pseudopotential(s)
# mentioned in the "files" file must correspond
# to the type(s) of atom.
#Definition of the atoms
natom 8 # There are eight atoms
typat 1 1 1 1 2 2 2 2
xred 0.00000000 0.00000000 0.00000000
0.23200000 0.73200000 0.50000000
0.50000000 0.23200000 0.73200000
0.73200000 0.50000000 0.23200000
0.71050000 0.71050000 0.71050000
0.52150000 0.02150000 0.21050000
0.21050000 0.52150000 0.02150000
0.02150000 0.21050000 0.52150000
#Definition of the planewave basis set
ecut 10.0 # Maximal kinetic energy cut-off, in Hartree
#Exchange-correlation functional
ixc 1 # LDA Teter Pade parametrization
#Definition of the k-point grid
kptopt 1 # Option for the automatic generation of k points, taking
# into account the symmetry
ngkpt 8 8 8 # This is a 8x8x8 FCC grid, based on the primitive vectors
toldfe 1.0d-8 # Will stop when, twice in a row, the difference
# between two consecutive evaluations of total energy
# differ by less than toldfe (in Hartree)
# This value is way too large for most realistic studies of materials
diemac 10
and with psp8 pseudopotentials downloaded from the Abinit website. However, instead of a smooth curve with a minimum I get something like
https://thumb.cloud.mail.ru/weblink/thumb/xw1/4kYB/rpc3mnD35/fesi.JPG?x-email=undefined
I have tried different pseudopotentials, ngkpt and ecut parameters seem to be high enough.
Any comments are welcome
Thank you in advance,
Anton F.