ABINIT Discussion Forums

Dear all,

I am trying to calculate a semiconductor EuO after reading a discussion: viewtopic.php?f=7&t=632
But a calculated density of state with DFT+U method for Eu shows that EuO is metal.
Do you have any idea for calculating the electron state of EuO properly with abinit.
I confirmed that FP-LAPW(elk) creates the correct DOS.
Are atomic orbitals necessary to calculate strong-correlation atoms like Eu?

The simulation detailed as follows:

First of all, I tried to use the no-semicore paw potential in viewtopic.php?f=7&t=632.
But I failed to generate 7 spin-up electrons for Eu.

Second, I created a semicore paw potential with the input files as follows:
(Actually, I modified an atompaw input file for Gd in the website of abinit to create the input file below.)
------------------------------------------------------------------------------------------
atompaw input file
------------------------------------------------------------------------------------------
Eu 63
GGA-PBE loggrid 2001 scalarrelativistic
6 5 5 4 0 0
5 2 0
4 3 7
0 0 0
c
c
c
c
v
v
c
c
c
v
c
c
v
v
3
2.50
n
y
2.0
n
y
2.0
n
y
2.0
n
VANDERBILT
4 0.0
2.45
2.45
2.45
2.45
2.45
2.45
2.45
2.45
0
------------------------------------------------------------------------------------------
abinit input file
------------------------------------------------------------------------------------------
ionmov 3
optcell 1
dilatmx 1.2
ecutsm 0.5
ntime 1000
tolmxf 5.0d-5

ixc 11
nsppol 2
occopt 7
tsmear 0.01

spinat 0.0 0.0 7.0 0.0 0.0 0.0
prtdos 1
nband 26

ecut 24
pawecutdg 60

kptopt 1
nshiftk 4
shiftk
0.5 0.5 0.5
0.5 0.0 0.0
0.0 0.5 0.0
0.0 0.0 0.5

ngkpt 4 4 4

#Definition of the unit cell
acell 3*9.7226
rprim
0.0 0.5 0.5
0.5 0.0 0.5
0.5 0.5 0.0

#Definition of the atom types
ntypat 2
znucl 63 8

#Definition of the atoms
natom 2 # There are two atoms
typat 1 2
xred
0.0 0.0 0.0
0.5 0.5 0.5

#Definition of the SCF procedure
nstep 300 # Maximal number of SCF cycles
toldfe 1.0d-6 # Will stop when, twice in a row, the difference

#PAW
# pawecutdg 100.

# LDA+U
usepawu 1
lpawu 3 -1
upawu 8.3 0.0 eV
jpawu 0.77 0.0 eV
------------------------------------------------------------------------------------------

While I successfully create 7 spin-up electrons in 4f orbital at Eu, the density of states show a metal.

*I picked up upawu and jpawu in Phys. Rev. B 77, 121202(2008).
This paper success in generating the proper electron states of EuO.

Any advice would be welcome, and thank you in advance.

Nakano.

I have evaluated the bands and DOS
by means of PBE0 approach with PAWs
with ABINIT code.
The LDA+U is the mean-field approximation,
depending of the Slater integrals, obtained from atomic data.
Application of the latter for crystals is
not a simple task because of the screening.
PBE0 partly removes the self-interaction, and therefore
improves the energy levels.
My attempts to calculate without of semicore states were
not successful.
With respect,
Steve.