[QE-users] K path of supercell

[Priya Shrivastava]

Dear Giuseppe

I really appreciate your response but unfolding the BS of supercell
was not my problem as

I have installed BandUP and tried to unfold but i faced few problems.

1. I put the high symmetry K-path points(from seek-path website
suitable for R3m symmetry) and unfolded but the band structures are
completely different for FCC unit cell and my supercell(1x1x2)

2. I used the FCC high symmetry path which gives me similar band
structure as of unit cell but one impurity band above the bandgap so
Is this method correct or whether i should go for 576 atoms
supercell(4x4x4) and then calculate EBS for supercell


@ dear Stefano

 I couldn't understand your purpose behind this "if “energy bands” makes any

sense in the presence of impurities..." Could you be so kind to elaborate?


Thanks

Priya

IITB,India







This being said, I doubt that the very concept if “energy bands” makes any
sense in the presence of impurities... SB

--
Stefano Baroni, Trieste -- swift message written and sent on the go

> On 28 Sep 2018, at 10:46, Giuseppe Mattioli <giuseppe.matti... at ism.cnr.it>
> wrote:
>
>
> Dear Priya
>
> Google is a good starting point for solving general-purpose problems:
> Supercells fold the unit cell band structure and make it difficult to compare
> with undoped band structures. If you type "unfolding supercell band
> structure" you find a lot of interesting tutorials. This one (among many
> other) might be useful to you
>
> https://www.ifm.liu.se/theomod/compphys/band-unfolding/
>
> HTH
> Giuseppe
>
> Priya Shrivastava <priyashrivastav... at gmail.com> ha scritto:
>
>> Dear all ,
>>
>> Please bear with me ( i m newbie) .I try to dope an fcc unit cell by making
>> supercell of 1x1x2. So the symmetry of supercell becomes R3m while unit
>> cell has fm-3m symmetry so is it correct that BZ would change for my
>> supercell and i can no longer use the k path that is provided for fcc unit
>> cell.
>>
>> if this is true what should i do because i would like to compare the band
>> structure of unitcell with supercell to see impurity effect.
>>
>> I tried to read kittel and several other things but i couldn't come to any
>> conclusion.please help.
>>
>> Thanks,
>> Priya
>
>
>
> GIUSEPPE MATTIOLI
> CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
> Via Salaria Km 29,300 - C.P. 10
> I-00015 - Monterotondo Scalo (RM)
> Mob (*preferred*) +39 373 7305625
> Tel + 39 06 90672342 - Fax +39 06 90672316
> E-mail: <giuseppe.matti... at ism.cnr.it>
>
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