[QE-users] I have failed to reproduce phonon dispersion of graphene

[Paolo Giannozzi]

On Tue, Mar 30, 2021 at 4:20 PM Evgenii <eisysoev4 at stud.eltech.ru> wrote:


>  Dielectric Tensor:
>
> ************************        166.332153320312          0.000000000000
>         166.332275390625************************          0.000000000000
>           0.000000000000          0.000000000000          1.116060253916
>

This is the expected behavior for a zero-gap crystal: the dielectric
constant diverges.


>
> Also, what is the best way to set the lattice parameters, via Ibrav or
> CELL_PARAMETERS?
>

they are equivalent[*], as long as you provide correct data; but, if you
specify the lattice parameters and atomic positions with the proper
symmetry you are less likely to run into trouble with symmetry in poorly
defined crystal structures.

Paolo

[*] but  allow me to declare that the setting celldm(1)=1.889726 to convert
from A to a.u. is abominable
-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20210330/f4a8eeab/attachment.html>