Wannier in abinit. Si and ZnSb March 3. 2011 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 #low ecut since this is a sample case # kpoint grid ngkpt 4 4 4 #grid of 4x4x4 kpoints #this is too low, you nshiftk 1 #just one shift is shiftk 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 !SHOULD PROBABLY EQUAL THE NUMBER OF OCCUPIED BANDS !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 2.91Å 2.8Å