[QE-users] Query regarding k path selection, mismatching of band gap

[Poonam Kaushik]

Dear Vahid Askarpour,
currently, I am trying by fixing occupation tetrahedra and fixed also. I'll
update here if everything works fine.
Thank you so much for your response and suggestion.

Thanks and regards,
Poonam Sharma




-------------------------------------------------------------------------------------------------
Poonam Sharma
Research Scholar
Department of Physics
Indian Institute of Technology Bombay
Mumbai - 400076
India.



On Wed, Oct 14, 2020 at 1:19 AM Poonam Kaushik <poonamkaushik40 at gmail.com>
wrote:

>
> Dear Expert,
> About the first option, I used to confuse to select the correct option for
> the occupation, smearing type, and broadening part. In my input file, I
> used an 'mv' smearing with a broadening of 0.02 Ry. So either I can reduce
> it to 0.01 Ry or  I can try any other occupation,  like tetrahedra or
> fixed. my system is an insulator with a small bandgap of 0.04 eV. Also in
> the third option, I calculated the k path by using the CIF file, and
> k-pathfinder. Please correct me if I am wrong.
>
> Thanks and regards,
> Poonam Sharma
>
>
>
>
>
> -------------------------------------------------------------------------------------------------
> Poonam Sharma
> Research Scholar
> Department of Physics
> Indian Institute of Technology Bombay
> Mumbai - 400076
> India.
>
>
>
> On Wed, Oct 14, 2020 at 12:18 AM Nicola Marzari <nicola.marzari at epfl.ch>
> wrote:
>
>> On 13/10/2020 20:43, Poonam Kaushik wrote:
>> > Dear Expert,
>> > So the only option that I have is to include the complete path and do
>> > the calculation again.
>> > Thank you so much for your suggestion.
>> >
>>
>> Mostly welcome, but you have three options - destiny can be generous
>> sometimes.
>>
>> The first option would be doing a more careful DOS:
>> https://www.quantum-espresso.org/Doc/INPUT_DOS.html
>>
>>                         nicola
>>
>> >
>> >
>> > Thanks and regards,
>> > Poonam Sharma
>> >
>> >
>> >
>> >
>> >
>> -------------------------------------------------------------------------------------------------
>> > Poonam Sharma
>> > Research Scholar
>> > Department of Physics
>> > Indian Institute of Technology Bombay
>> > Mumbai - 400076
>> > India.
>> >
>> >
>> >
>> > On Tue, Oct 13, 2020 at 11:53 PM Nicola Marzari <nicola.marzari at epfl.ch
>> > <mailto:nicola.marzari at epfl.ch>> wrote:
>> >
>> >
>> >
>> >
>> >       From the most to the less likely, it could be that your DOS has
>> some
>> >     broadening that masks the existence of a small gap, or that the gap
>> >     closes across the last two segments of the path that you are
>> >     missing, or
>> >     that you are very unlucky and the band gaps closes at points that do
>> >     not
>> >     lie on a high symmetry path.
>> >
>> >                   nicola
>> >
>> >
>> >     On 13/10/2020 19:53, Poonam Kaushik wrote:
>> >      >
>> >      > Dear Experts,
>> >      >   I have one query regarding k path selection. After using Kpath
>> >     finder
>> >      > (https://www.materialscloud.org/work/tools/seekpath ), i got
>> >     this type
>> >      > of  k path
>> >      > G-M-K-G-A-L-H-A|L-M|H-K for my structure. In the calculation, I
>> >     used, up
>> >      > to G-M-K-G-A-L-H-A. So, is this ok to select a path up to this?
>> >      > Basically in the band structure, I am getting some finite gap
>> >     while in
>> >      > dos I m getting a zero bandgap, after selecting the path up to
>> >      > G-M-K-G-A-L-H-A. I am not able to figure out why this is
>> happening?
>> >      > Should it help to include the complete path? I am attaching here
>> my
>> >      > input file, band structure, and dos. Please have a look.
>> >      >
>> >      >
>> >
>> https://drive.google.com/drive/folders/1UhUgod8KnvdovJfxMqbJMQwdtb3dE-yY
>> >      >
>> >      >   I'll be very thankful for any suggestions.
>> >      >
>> >      > Thanks and regards,
>> >      > Poonam Sharma
>> >      >
>> >      >
>> >      >
>> >      >
>> >
>>  -------------------------------------------------------------------------------------------------
>> >      > Poonam Sharma
>> >      > Research Scholar
>> >      > Department of Physics
>> >      > Indian Institute of Technology Bombay
>> >      > Mumbai - 400076
>> >      > India.
>> >      >
>> >      >
>> >      > _______________________________________________
>> >      > Quantum ESPRESSO is supported by MaX (www.max-centre.eu
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>> >
>> >
>> >     --
>> >
>>  ----------------------------------------------------------------------
>> >     Prof Nicola Marzari, Chair of Theory and Simulation of Materials,
>> EPFL
>> >     Director, National Centre for Competence in Research NCCR MARVEL,
>> EPFL
>> >     http://theossrv1.epfl.ch/Main/Contact
>> http://nccr-marvel.ch/en/project
>> >
>>
>>
>> --
>> ----------------------------------------------------------------------
>> Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
>> Director, National Centre for Competence in Research NCCR MARVEL, EPFL
>> http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project
>>
>
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