Dear Binghai,<div><br></div><div>Maybe the issue is related to the convergence, the off-diagonal matrix elements you show have a non-null imaginary part, as far as I know this means that the Wannier functions you got are not still the maximally localized ones since these should be real in a system with TR symmetry (see PRL 98, 046402 (2007)). Maybe you could try to wannierise till the imaginary part of the matrix elements are null to be sure that you got the MLWF, and then check the on-site and off-diagonal matrix elements. Just a question, the 16 bands you are including, are they all below the Fermi level?</div>
<div><br></div><div>Cheers,</div><div><br></div><div>Julen</div><div><br><br><div class="gmail_quote">On Fri, Nov 9, 2012 at 11:44 AM, Yan, Binghai <span dir="ltr"><<a href="mailto:yanb@uni-mainz.de" target="_blank">yanb@uni-mainz.de</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear Wannier developers<br>
<br>
I am new user of wannier90. I extract wannier functions from a DFT calculation (I use vasp) including spin orbit coupling (SOC). Then I switch on spinors=T and double the num_bands.<br>
My systems have no spin polarization, respecting the time reversal symmetry. A wannier function is expected to be represented by two functions, which have the same center but different spins. I expect these two functions have the same onsite energies and the hopping term between them are exactly zero.<br>
However, I get different onsite energies and nonzero hopping terms, although the band structure is well reproduced. The wannier cenceters are also very different.<br>
<br>
The following is an example of my inputs for bulk HgTe calculations. (zincblende structure)<br>
<br>
==========<br>
num_wann = 16<br>
num_bands = 38<br>
#exclude_bands = 3-12<br>
<br>
dis_win_max = 15.0<br>
dis_froz_max = 9<br>
dis_num_iter = 2000<br>
dis_mix_ratio = 1.d0<br>
<br>
num_iter = 1000<br>
num_print_cycles = 10<br>
<br>
Begin Projections<br>
Hg : sp3<br>
Te : sp3<br>
End Projections<br>
<br>
spinors = .true.<br>
<br>
begin unit_cell_cart<br>
3.2300000 3.2300000 0.0000000<br>
0.0000000 3.2300000 3.2300000<br>
3.2300000 0.0000000 3.2300000<br>
end unit_cell_cart<br>
<br>
begin atoms_cart<br>
Hg 2.4225000 2.4225000 2.4225000<br>
Te 4.0375000 4.0375000 4.0375000<br>
end atoms_cart<br>
<br>
mp_grid = 12 12 12<br>
<br>
begin kpoints<br>
0.000000000000 0.000000000000 0.000000000000<br>
0.083333333333 0.000000000000 0.000000000000<br>
0.166666666667 0.000000000000 0.000000000000<br>
0.250000000000 0.000000000000 0.000000000000<br>
................<br>
========================<br>
<br>
The optimized wannier centers are :<br>
Cycle: 1000<br>
WF centre and spread 1 ( 1.125081, 2.105459, 2.107134 ) 7.50544434<br>
WF centre and spread 2 ( 2.108857, 1.123510, 2.103942 ) 7.50493864<br>
WF centre and spread 3 ( 2.106035, 2.107794, 1.122418 ) 7.50768700<br>
WF centre and spread 4 ( 1.124096, 1.124214, 1.123910 ) 7.52064335<br>
WF centre and spread 5 ( 3.522963, 3.524601, 3.524535 ) 4.48040046<br>
WF centre and spread 6 ( 3.526018, 2.934456, 2.939037 ) 4.47399171<br>
WF centre and spread 7 ( 2.939672, 3.523541, 2.932669 ) 4.46863560<br>
WF centre and spread 8 ( 2.934153, 2.938291, 3.522491 ) 4.47010302<br>
WF centre and spread 9 ( 2.107155, 2.105137, 1.125272 ) 7.64204572<br>
WF centre and spread 10 ( 1.123133, 1.123929, 1.123907 ) 7.64532973<br>
WF centre and spread 11 ( 1.122550, 2.106696, 2.105047 ) 7.63263662<br>
WF centre and spread 12 ( 2.104217, 1.123646, 2.107754 ) 7.63564195<br>
WF centre and spread 13 ( 3.524860, 3.524017, 3.523515 ) 4.51698438<br>
WF centre and spread 14 ( 3.522838, 2.936705, 2.934278 ) 4.51145886<br>
WF centre and spread 15 ( 2.933391, 3.524025, 2.938085 ) 4.50864047<br>
WF centre and spread 16 ( 2.937251, 2.934720, 3.525198 ) 4.51260402<br>
Sum of centres and spreads ( 38.762270, 38.760740, 38.759191 ) 96.53718585<br>
<br>
For example, the matrix elements between WF 8 and WF 16 are<br>
<br>
0 0 0 8 8 0.863620 0.000000<br>
-<br>
0 0 0 16 16 0.932080 0.000000<br>
-<br>
0 0 0 16 8 -0.032312 -0.000905<br>
-<br>
0 0 0 8 16 -0.032312 0.000905<br>
<br>
<br>
Is this problem due to a bad projection? Actually, I used sp3 for non-SOC case, it seems pretty well.<br>
Is there a way to constrain different spins have the same wannier centers?<br>
<br>
Thank you very much in advance!<br>
Binghai<br>
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</blockquote></div><br></div><br clear="all"><div><br></div>-- <br>========================================<br> Julen Ibańez Azpiroz<br> Materia Kondentsatuaren Fisika Saila<br>
Zientzia eta Teknologia Fakultatea<br>
Euskal Herriko Unibertsitatea<br> ========================================<br>