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Dear Tobias,
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<div class="">In general you would need to apply constraints, either to the symmetry of the WFs (as in the work of Sakuma that you mention below), of by explicitly constraining the centres (as proposed in a recent paper by Marianetti et al,
<a href="http://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.165125" class="">
http://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.165125</a>). Unfortunately, neither approach is implemented in the main code at present.</div>
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<div class="">Best wishes,</div>
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<div class="">Arash</div>
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<div class="">Arash Mostofi — <a href="http://www.mostofigroup.org" class="">www.mostofigroup.org</a></div>
<div class="">Reader in Theory and Simulation of Materials</div>
<div class="">Imperial College London</div>
<div class="">Director, Thomas Young Centre @Imperial</div>
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<blockquote type="cite" class="">
<div class="">On 17 Dec 2015, at 14:31, Tobias Frank <<a href="mailto:pike.lucius@gmail.com" class="">pike.lucius@gmail.com</a>> wrote:</div>
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<div dir="ltr" class=""><span style="font-size:12.8px" class="">Dear wannier90 users,</span>
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<div style="font-size:12.8px" class="">I currently try to wannierize MoS2, which has a disconnected band manifold of 11 bands (5 Mo d orbitals and 2*3 S p orbitals).</div>
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<div class=""> *----------------------------------------------------------------------------*</div>
<div class=""> | Site Fractional Coordinate Cartesian Coordinate (Ang) |</div>
<div class=""> +----------------------------------------------------------------------------+</div>
<div class=""> | Mo 1 0.33333 0.66667 0.50000 | -0.00000 1.84059 12.50000 |</div>
<div class=""> | S 1 0.66667 0.33333 0.56240 | 1.59400 0.92030 14.05992 |</div>
<div class=""> | S 2 0.66667 0.33333 0.43760 | 1.59400 0.92030 10.94008 |</div>
<div class=""> *----------------------------------------------------------------------------*</div>
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<div style="font-size:12.8px" class="">The goal is to get a symmetric tight-binding Hamiltonian (_hr.dat) out of the calculation. The scheme I use is to project onto atomic orbitals without any maximal localization iteration applied ("symmetry adapted wannier
functions") and guiding centers are turned on.</div>
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<div style="font-size:12.8px" class="">My initial (and final) state reads:</div>
<div style="font-size:12.8px" class="">projections:Mo:d, S:p</div>
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<div class=""> Initial State</div>
<div class=""> WF centre and spread 1 ( -0.000000, 1.840629, 12.500000 ) 1.65212451</div>
<div class=""> WF centre and spread 2 ( -0.000000, 1.797275, 12.500000 ) 1.88788741</div>
<div class=""> WF centre and spread 3 ( -0.000000, 1.883825, 12.500000 ) 1.88514896</div>
<div class=""> WF centre and spread 4 ( -0.000000, 1.744405, 12.500000 ) 1.79754077</div>
<div class=""> WF centre and spread 5 ( -0.000000, 1.936664, 12.500000 ) 1.79758431</div>
<div class=""> WF centre and spread 6 ( 1.594000, 0.920313, 14.121223 ) 1.69614206</div>
<div class=""> WF centre and spread 7 ( 1.594000, 0.932663, 14.015563 ) 1.56344882</div>
<div class=""> WF centre and spread 8 ( 1.594000, 0.908001, 14.015556 ) 1.56201127</div>
<div class=""> WF centre and spread 9 ( 1.594000, 0.920313, 10.878777 ) 1.69614206</div>
<div class=""> WF centre and spread 10 ( 1.594000, 0.932663, 10.984437 ) 1.56344882</div>
<div class=""> WF centre and spread 11 ( 1.594000, 0.908001, 10.984444 ) 1.56201127</div>
<div class=""> Sum of centres and spreads ( 9.564000, 14.724751,137.500000 ) 18.66349025</div>
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<div style="font-size:12.8px" class="">This yields a very good description of the band structure, but why are the initial projections not exactly at the atomic sites, where I specified them to be? This slight asymmetry reflects also in the tight-binding matrix
elements, where I would like to have symmetric ones. Could you give me a hint how to get the wannier centers at the atomic positions?</div>
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<div style="font-size:12.8px" class="">I am aware about the publication of Sakuma ("Symmetry-adapted Wannier functions in the maximal localization procedure"). I am using Quantum Espresso, where it is not implemented. Is there any work on the way?</div>
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<div style="font-size:12.8px" class="">Thank you very much,<br class="">
Tobias Frank</div>
<div style="font-size:12.8px" class="">PhD student</div>
<div style="font-size:12.8px" class="">Universität Regensburg</div>
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