Electron poor materials research group
Wannier in abinit.
Si and ZnSb
March 3. 2011
Procedure
• Steal relaxed structure from VASP calculation
• Run Abinit to get the maximally locallized
wannier functions (MLWF).
• Search through the output bands for wannier
functions that are located in places of interest.
– This is done via an overlap with another function
that has an object located at the place of interest.
• This was done for Si and ZnSb.
Si “INCAR”
ndtset
2
# Silicon structure
acell 10.333 10.333 10.333
rprim
0.00 0.50 0.50
0.50 0.00 0.50
0.50 0.50 0.00
natom
2
xred
0.00 0.00 0.00
0.25 0.25 0.25
ntypat
1
typat
1
1
znucl 14.00
symmorphi
0
# Plane wave basis
ecut
12.00
# kpoint grid
ngkpt
444
nshiftk
shiftk
#low ecut since this is a sample case
#grid of 4x4x4 kpoints
#this is too low, you
1
#just one shift is
0.00 0.00 0.00 #no shift
Si “INCAR” continued…
# Self-consistent run to get the density
iscf1 5
nstep1 150
tolvrs1 1.00d-12 #Tolerance for convergence
nband1 5
prtden1 1
diemac1 12.0 #Preconditioner for scf
kptopt1 1
istwfk1 8*1 #Controls the form of the wavefunctions
# Second: Wannier90
iscf2 -2 #nscf run
nstep2 0
#just read the old wave functions
tolwfr2 1.e-10 #dummy here
getwfk2 1
getden2 1 # Usual file handling data
prtwant2 2 # Call to Wannier90
nband2 4
istwfk2 64*1 #Controls the form of the wavefunctions
kptopt2 3 # Option for the automatic generation of k points
w90prtunk2 1 #Prints UNK files (for plotting the Wannier
wannier.win
num_wann 68
BANDS
!SHOULD PROBABLY EQUAL THE NUMBER OF OCCUPIED
!CONVERGENCE
num_iter 5000 !MAXIMUM NUMBER OF TOTAL ITERATIONS
num_cg_steps 20 !NUMBER OF CG STEPS BEFORE STEEPEST DESCENT
conv_window 2 !>1 MEANS STOP CONVERGENCE WHEN DELTA < conv_tol
conv_tol 1E-12
conv_noise_amp 10 !ADDS RANDOM NOISE AFTER CONVERGENCE AT conv_tol
!AND RECONVERGES TO MAKE SURE THE MINIMUM IS REACHED
!plotting
wannier_plot = true
wannier_plot_supercell = 2 !how far out to plot the wannier functions
Si Wannier States
ZnSb wannier spheres for overlap
Wannier overlap with spheres
ZnSb 3centers
Contour Image of wannier in ZnSb