1. Wannier in abinit. Si and ZnSb March 3. 2011
Electron poor materials research group
Wannier in abinit.
Si and ZnSb
March

2. 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.

3. Si “INCAR” ndtset 2 # Silicon structure acell 10.333 10.333 10.333
rprim
natom
xred
ntypat
typat
znucl
symmorphi
# Plane wave basis
ecut #low ecut since this is a sample case
# kpoint grid
ngkpt #grid of 4x4x4 kpoints
#this is too low, you
nshiftk #just one shift is
shiftk #no shift

4. Si “INCAR” continued… # Self-consistent run to get the density iscf1 5
nstep
tolvrs d-12 #Tolerance for convergence
nband1 5
prtden1 1
diemac #Preconditioner for scf
kptopt1 1
istwfk1 8*1 #Controls the form of the wavefunctions
# Second: Wannier90
iscf #nscf run
nstep #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

5. wannier.win
num_wann !SHOULD PROBABLY EQUAL THE NUMBER OF OCCUPIED BANDS
!CONVERGENCE
num_iter !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

6. Si Wannier States

7. ZnSb wannier spheres for overlap

8. Wannier overlap with spheres

9. ZnSb 3centers

10. Contour Image of wannier in ZnSb
2.91Å
2.8Å