[Wannier] large Im/Re

[Jennifer Wohlwend]

Dear all,

I'm using WANNIER90 (Release: 1.1.1) as a library with pwscf and epw.x for Copper. Although I'm using the same starting projections as the example (I've also tried starting with 'random') with  15 bands (7 WFs) and an 8x8x8 k-point mesh the Im/Re ratio is still quite high especially for the interstitial WF (6 and 7).  The spread is also somewhat larger than the example found here: http://www.tcm.phy.cam.ac.uk/~jry20/wannier/copper.html.

The band structure reproduces well and the visualization of the (1-5) WF look like 3dx2-y2 , 3dz2 , 3dxy, 3dxz, and 3dyz orbitals whereas the 6 & 7 WF look like distorted s orbitals. I've included guiding_centres = T as well but I'm still getting imaginary WF. I have included the center/spread data, Im/Re ratio data, the .win file created by epw.x as well as the pwscf.in file for my system. Thank you in advance for any suggestions on how to remedy this situation.

 Final State
  WF centre and spread    1  (  0.000000,  0.000000,  0.000000 )     0.47410645
  WF centre and spread    2  (  0.000000,  0.000000,  0.000000 )     0.45976002
  WF centre and spread    3  (  0.000000,  0.000000,  0.000000 )     0.45976002
  WF centre and spread    4  (  0.000000,  0.000000,  0.000000 )     0.47410482
  WF centre and spread    5  (  0.000000,  0.000000,  0.000000 )     0.45975935
  WF centre and spread    6  ( -0.889018,  0.889018,  0.889018 )     1.83568265
  WF centre and spread    7  (  0.889018, -0.889018, -0.889018 )     1.83568265
  Sum of centres and spreads (  0.000000,  0.000000,  0.000000 )     5.99885597

         Spreads (Ang^2)       Omega I      =     5.398459543
        ================       Omega D      =     0.006910496
                               Omega OD     =     0.593485936
    Final Spread (Ang^2)       Omega Total  =     5.998855975
 ------------------------------------------------------------------------------

  Omega Invariant:   1-s^2 =     5.398459543 (Ang^2)
                   -2log s =     5.917906434 (Ang^2)
                    acos^2 =     5.729169696 (Ang^2)
      Wannier Function Num:    1       Maximum Im/Re Ratio =    0.075234
      Wannier Function Num:    2       Maximum Im/Re Ratio =    0.632363
      Wannier Function Num:    3       Maximum Im/Re Ratio =    0.718934
      Wannier Function Num:    4       Maximum Im/Re Ratio =    0.071312
      Wannier Function Num:    5       Maximum Im/Re Ratio =    1.014505
      Wannier Function Num:    6       Maximum Im/Re Ratio =    2.203505
      Wannier Function Num:    7       Maximum Im/Re Ratio =    3.094914
***.win file:

begin projections
 Cu:d
 f=0.25,0.25,0.25:s
 f=-0.25,-0.25,-0.25:s
end projections
num_wann   7
iprint   5
dis_win_min     0.000
dis_win_max    40.000
dis_froz_min     0.000
dis_froz_max    20.000
num_iter    3000
search_shells      20
 Begin Kpoint_Path

 G 0.00  0.00  0.00    X 0.50  0.50  0.00

 X 0.50  0.50  0.00    W 0.75  0.50  0.25

 W 0.75  0.50  0.25    L 0.50  0.50  0.50

 L 0.50  0.50  0.50    G 0.00  0.00  0.00

 G 0.00  0.00  0.00    K 0.75  0.3750 0.3750

 End Kpoint_Path

  bands_plot = .true.

 wannier_plot = true

 num_bands       = 15

 dis_num_iter=9000

 dis_mix_ratio=0.2

 guiding_centres = T

 

***pwscf.in:

 &control
    calculation='scf',
    prefix='Cu',
    pseudo_dir = '../../pp/',
    outdir='./',
 /
 &system
    ibrav = 2 ,
    celldm(1) = 6.72 ,
    nat=  1 ,
    ntyp = 1 ,
    ecutwfc = 80.0
    occupations = 'smearing',
    smearing = 'marzari-vanderbilt'
    nbnd = 15
    degauss = 0.001
    nosym=.true.
 /
 &electrons
    mixing_beta = 0.1
    conv_thr =  1.0d-8
 /
ATOMIC_SPECIES
 Cu 63.55  Cu.pw-mt_fhi.UPF
ATOMIC_POSITIONS crystal
Cu        0.000000000   0.000000000   0.000000000
K_POINTS AUTOMATIC
16 16 16 0 0 0



Thank you!!

Jennifer

 

Jennifer L. Wohlwend
Universal Technology Corporation 		 	   		  
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