question haldane model

[Dominik Gresch]

Dear Rafael González,

When an integer is passed to the "bands" flag, it is interpreted as the
/number/ of bands to take into account. In your example

  * bands=0: is equivalent to bands=[] - there are no bands to compute
    the Chern number for, which is why it doesn't work
  * bands=1: is equivalent to bands=[0] - it computes the Chern number
    for the lower-energy bands
  * bands=[1] computes the Chern number for the higher-energy band
    (i.e., unoccupied) band - which has the opposite value
  * bands=[0,1] (equivalent to bands=2) - when the whole system (all
    bands) are included, it can be adiabatically connected to a trivial
    system

I hope this helps - let me know if things are still unclear.

Best regards,

Dominik

On 03.08.20 20:59, Rafael Gonzalez Hernandez wrote:
> Dear z2pack,
> I used the code to understand the example of Haldane model.
> However, I changed the bands flag to test it and I found the Chern
> number for different values of:
>
> band=0 chern= doesn't work
> band=1 chern=-1
> band=[0] chern=-1
> band=[1] chern=1
> band=[0,1] chern=0
>
> Why It is finding found a different between 1(both bands according to
> manual) and [0,1] bands?
> Thank you in advance for your help
>
> Best regards,
> --
> Resultado de imagen para uninorte logo
>
>
> Rafael J. González Hernández
>
> Profesor Asociado
> Departamento de Física. Of. 2-45. Bloque L-6.
> Tel. +57 5 3509509  Ext. 3425
> E <http://www.uninorte.edu.co/>mail: rhernandezj at uninorte.edu.co
> <mailto:rhernandezj at uninorte.edu.co>
>
>
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