[Wannier] What is a good value for final spread?
Cuauhtemoc Salazar
salazar at physics.utoronto.ca
Mon Mar 14 07:48:11 CET 2016
Dear All,
I wonder if someone could if tell me if having MLWF’s with spreads between 5 and 8 Angs^2 is considered insufficiently localized for further computation of physical properties.
I have let run the wannierization for num_iter in the order of few thousands and the MLWF's don’t get more localized (indeed, the spreads reach convergence with a few hundred iterations). I think my initial guess for the projections is reasonable, since it is based on the orbital character of the bands I included in the Wannierization. As a check, I got the Wannier-interpolated bandstructure and it is in good agreement with the ab-initio bands.
DETAILS: I have computed MLWF for stanene, a monolayer of Tin atoms (Z=50), including spin-orbit coupling and d-electrons in the valence (Z_ion=14), using NCPP -Vanderbilt pseudo potentials. The lattice and plane wave parameters were carefully relaxed / converged, using the expresso suite. The disentanglement convergence criteria is satisfied after about 500 iterations, with a
Final Omega_I 45.08612336 (Ang^2)
The Wannierization ends with a
Final State
WF centre and spread 1 ( 2.664805, -0.000003, 0.419178 ) 4.67225286
WF centre and spread 2 ( 2.664807, -0.000002, 0.419224 ) 4.67237620
WF centre and spread 3 ( 1.748739, 1.587314, -0.120711 ) 7.50851491
WF centre and spread 4 ( 1.748760, 1.587282, -0.120730 ) 7.50791412
WF centre and spread 5 ( 1.748742, 3.028131, -0.120725 ) 7.50859427
WF centre and spread 6 ( 1.748763, 3.028160, -0.120744 ) 7.50800753
WF centre and spread 7 ( 0.499489, 2.307780, -0.120057 ) 7.51866504
WF centre and spread 8 ( 0.499439, 2.307777, -0.120072 ) 7.51823175
Sum of centres and spreads ( 13.323545, 13.846439, 0.115362 ) 54.41455668
Spreads (Ang^2) Omega I = 45.086123364
================ Omega D = 2.035781370
Omega OD = 7.292651945
Final Spread (Ang^2) Omega Total = 54.414556679
##########
The wannier90 input file includes
spinors = true
dis_num_iter = 900 ! needs about 500
num_iter = 5000 ! 5,000
guiding_centres = true
Begin Projections
Sn1: pz ! one orbital
Sn2: sp2 ! three orbitals
End Projections
! since we have spin, the number of projections is num_wann/2 = 4
I am using PWSCF v.5.3.0 and wannier90 2.0.1.
With regards,
Cuauhtemoc Salazar
PhD Candidate
University of Toronto
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