Calculate Chern number with an odd number occupied bands in a system

[Dominik Gresch]

Dear Xiangru,

This is a limitation from Wannier90 -- with spinor = true, you can only 
run systems with an even number of Wannier functions. You should be able 
to get around this limitation by adding the first band to the list of 
excluded bands (exclude_bands parameter).

The issue is not related to whether you want to calculate the Chern 
number or different topological invariants.

Best regards,

Dominik


On 07.03.2017 07:09, xiangru kong wrote:
> Dear Dominik,
>
>  Could Z2pack directly calculate the Chern number with first principle 
> codes?
>
> I have considered a system with odd number occupied bands (with SOC 
> considered), I set the related parameters the similiar way as the Z2 
> calculation.
>
>     surface=lambda s, t: [ s, t, 0]
>     z2pack.invariant.chern(result_0)
>
>
> and
>
>     num_wann=num_bands= the number of occupied bands (odd)
>
>
> The error happens in wannier90.wout
>
>
>     Error: For spinor WF num_wann ust be even
>
>
> Maybe the intrinsic physic in the Chern number I have not known.
>
> Thanks
>
> Xiangru
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.phys.ethz.ch/private/z2pack/attachments/20170307/0ea6ec3e/attachment.html>