Re: [Wien] Need help; Supercell's folded band structure.

2015-10-01 Thread Oleg Rubel 
Hello Youngboem,

it would be useful to include the band structure plots from your attempts. 
Otherwise it is hard to guess what went wrong.

Also, before plotting, it will be helpful to look at a part of the output that 
contains the Bloch spectrum weights for the conduction band maximum and the 
valence band minimum.

Fold2Boch runs in two modes complex (default) and real. In case your 2x2x2 
supercell has the inversion symmetry (check structure file for a diagonal 
matrix with -1), you will need to activate the real version.


Thank you
Oleg

> On Oct 1, 2015, at 05:28, Peter Blaha  wrote:
> 
> Clearly your solution isfold2bloch.
> 
> If you don't like the plot, you have to modify this part yourself and make a 
> different plot, but fold2bloch captures all the relevant physics which 
> happens due to doping. Doping may lead to a "broadening" of bands when you 
> introduce alloying (and represent it in the original BZ).
> 
> Otherwise you have to write your own code, but the basis will always be like 
> fold2bloch (check their paper for some deeper understanding about "Bloch 
> functions" and folding )
> http://arxiv.org/abs/1405.4218
> 
> 
> 
> On 10/01/2015 10:54 AM, Youngboem Cho wrote:
>> Hi. I can solve many technical problems by all your helps. Thank you
>> very much..!
>> Now new problem emerged in front of me.
>> Very simple problem but unfortunately, it's too hard to solve for me.
>> 
>> "How can I unfold the band structure made in 2x2x2 or some structure by
>> 'supercell'? (without fold2bloch)"
>> 
>> I guess that this folded band is caused by shortened reciprocal vectors.
>> For example, Ge's minimum conduction band's energy is located at L-valley.
>> but after I made it be 2x2x2 structure, lattice parameter is doubled
>> that it makes reciprocal vectors 1/2 shortened.
>> so when I calculate and see the 2x2x2 Ge's band structure, it look weird.
>> (Actually Ge's minimum conduction band's energy is located at L-valley
>> but this 2x2x2 shows me
>> weired location; Gamma-valley is the lowest conduction band energy!)
>> (I think maybe it misunderstood the true L-point. it just calculate
>> until L-point*1/2 and then finished. am I right?)
>> 
>> 1) So I doubled the 'm' in (m*kx m*ky m*kz)
>> but this made the band structure just folded.
>> 2) I used 'Fold2bloch'. but this doesn't seems beautiful for me
>> (I want to make 2x2x2's band structure just like 1x1x1's band structure.)
>> 
>> All this efforts are for alloy's band structures.
>> It seems to need use 'supercell' For under 1% of alloy. so I have to
>> solve this problem.
>> 
>> Is there any good suggestion?
>> 
>> thank you for reading!
>> 
>> 
>>- Sincerely
>> Youngboem Cho
>> 
>> 
>> ___
>> Wien mailing list
>> Wien@zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>> SEARCH the MAILING-LIST at:
>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
> 
> -- 
> 
>  P.Blaha
> --
> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
> Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
> Email: bl...@theochem.tuwien.ac.atWIEN2k: http://www.wien2k.at
> WWW:   http://www.imc.tuwien.ac.at/staff/tc_group_e.php
> --
> ___
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> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> SEARCH the MAILING-LIST at:  
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Re: [Wien] Need help; Supercell's folded band structure.

2015-10-01 Thread Peter Blaha 

Clearly your solution isfold2bloch.

If you don't like the plot, you have to modify this part yourself and 
make a different plot, but fold2bloch captures all the relevant physics 
which happens due to doping. Doping may lead to a "broadening" of bands 
when you introduce alloying (and represent it in the original BZ).


Otherwise you have to write your own code, but the basis will always be 
like fold2bloch (check their paper for some deeper understanding about 
"Bloch functions" and folding )

http://arxiv.org/abs/1405.4218



On 10/01/2015 10:54 AM, Youngboem Cho wrote:

Hi. I can solve many technical problems by all your helps. Thank you
very much..!
Now new problem emerged in front of me.
Very simple problem but unfortunately, it's too hard to solve for me.

"How can I unfold the band structure made in 2x2x2 or some structure by
'supercell'? (without fold2bloch)"

I guess that this folded band is caused by shortened reciprocal vectors.
For example, Ge's minimum conduction band's energy is located at L-valley.
but after I made it be 2x2x2 structure, lattice parameter is doubled
that it makes reciprocal vectors 1/2 shortened.
so when I calculate and see the 2x2x2 Ge's band structure, it look weird.
(Actually Ge's minimum conduction band's energy is located at L-valley
but this 2x2x2 shows me
weired location; Gamma-valley is the lowest conduction band energy!)
(I think maybe it misunderstood the true L-point. it just calculate
until L-point*1/2 and then finished. am I right?)

1) So I doubled the 'm' in (m*kx m*ky m*kz)
but this made the band structure just folded.
2) I used 'Fold2bloch'. but this doesn't seems beautiful for me
(I want to make 2x2x2's band structure just like 1x1x1's band structure.)

All this efforts are for alloy's band structures.
It seems to need use 'supercell' For under 1% of alloy. so I have to
solve this problem.

Is there any good suggestion?

thank you for reading!


- Sincerely
Youngboem Cho


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--

  P.Blaha
--
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
Email: bl...@theochem.tuwien.ac.atWIEN2k: http://www.wien2k.at
WWW:   http://www.imc.tuwien.ac.at/staff/tc_group_e.php
--
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