Re: [Wien] Graphene bandstructure

[Islam, Md F]

Hi Prof Blaha,

I have got the gap from plotting bandstructure as well as DOS calculations.
I can see the linear dispersion at the K point just like the way it is suppose 
to be
when I plot all the bands in eV range. But if I zoom in at the K point in meV 
range,
I can see the gap.  

   I don't think there is anything wrong with the structure. I did check all 
bond lengths,
angles before I ran the calculations and they are correct. I suspect I may have 
to adjust 
parameters. I started to see some difference with LDA xc functional with larger 
k mesh.


Thanks,
Fhokrul  
 




From: wien-boun...@zeus.theochem.tuwien.ac.at 
[wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of Peter Blaha 
[pbl...@theochem.tuwien.ac.at]
Sent: Tuesday, December 22, 2015 11:35 AM
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] Graphene bandstructure

Graphene is metallic by "symmetry", i.e. EF is at a 2-fold eigenvalue at
the K-point and bands cross with a linear dispersion.

 From where do you know that graphene has a gap in your calculations ??

 From :gap in the scf file or from plotting the bandstructure or ...

It the state at K is not degenerate, you have the wrong symmetry and are
not doing graphene.

Am 22.12.2015 um 16:51 schrieb Islam, Md F:
> Hi,
>
>   I am trying to do a bandstructure calculation of graphene to check if I 
> can
> reproduce results discussed in literature (I am using a unit cell of 2 atoms).
> With spin-orbit coupling, there should be a gap of the order of few micro-eV
> and without spin-orbit, there should not be any gap at Dirac point. But I am
> getting a gap of meV even without spin-orbit. I tried both GGA and LDA with
> very dense mesh but the gap does not close. So I am wondering if anyone
> have any suggestion about how to do it in Wien2k.
>
>
> Thanks,
> Fhokrul
> ___
> 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
>

--
--
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
--
___
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
___
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

[Wien] Error in initialization stage

[Hu, Wenhao]

Hi, All:

I met a problem in the initialization stage. I’m currently testing the effect 
of distance between clusters in nano wire calculation. When the distance is 
small (size of unit cell is small), everything is initialized properly. When I 
increase the distance until the size of unit cell is as large as 70x70x30 in 
bohr, I met the following problem:

dstart -c -p(14:31:23) running dstart in single mode
Segmentation fault
13.207u 0.136s 0:13.62 97.8%0+0k 0+18312io 0pf+0w
error: command   /Users/wenhhu/wien2k14/dstartpara -c start.def   failed

Can anyone tell what is this error? And How can we solve it?

Best,
Wenhao
___
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

Re: [Wien] Graphene bandstructure

[Peter Blaha]

The two eigenvalues at K must be identical by symmetry.

If you have a splitting of some meV it means that your structure is 
slightly wrong.


Typical errors: positions of 1/3 and 2/3 must be given in full precision.
 0.   is NOT 1/3

Am 22.12.2015 um 20:31 schrieb Islam, Md F:

Hi Prof Blaha,

 I have got the gap from plotting bandstructure as well as DOS calculations.
I can see the linear dispersion at the K point just like the way it is suppose 
to be
when I plot all the bands in eV range. But if I zoom in at the K point in meV 
range,
I can see the gap.

I don't think there is anything wrong with the structure. I did check all 
bond lengths,
angles before I ran the calculations and they are correct. I suspect I may have 
to adjust
parameters. I started to see some difference with LDA xc functional with larger 
k mesh.


Thanks,
Fhokrul





From: wien-boun...@zeus.theochem.tuwien.ac.at 
[wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of Peter Blaha 
[pbl...@theochem.tuwien.ac.at]
Sent: Tuesday, December 22, 2015 11:35 AM
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] Graphene bandstructure

Graphene is metallic by "symmetry", i.e. EF is at a 2-fold eigenvalue at
the K-point and bands cross with a linear dispersion.

  From where do you know that graphene has a gap in your calculations ??

  From :gap in the scf file or from plotting the bandstructure or ...

It the state at K is not degenerate, you have the wrong symmetry and are
not doing graphene.

Am 22.12.2015 um 16:51 schrieb Islam, Md F:

Hi,

   I am trying to do a bandstructure calculation of graphene to check if I 
can
reproduce results discussed in literature (I am using a unit cell of 2 atoms).
With spin-orbit coupling, there should be a gap of the order of few micro-eV
and without spin-orbit, there should not be any gap at Dirac point. But I am
getting a gap of meV even without spin-orbit. I tried both GGA and LDA with
very dense mesh but the gap does not close. So I am wondering if anyone
have any suggestion about how to do it in Wien2k.


Thanks,
Fhokrul
___
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



--
--
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
--
___
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
___
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



--
--
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
--
___
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

Re: [Wien] Error in initialization stage

[Peter Blaha]

You are running out of memory.
You cannot run 70x30x30 unit cells on a PC and in sequential mode.

Am 22.12.2015 um 22:00 schrieb Hu, Wenhao:

Hi, All:

I met a problem in the initialization stage. I’m currently testing the effect 
of distance between clusters in nano wire calculation. When the distance is 
small (size of unit cell is small), everything is initialized properly. When I 
increase the distance until the size of unit cell is as large as 70x70x30 in 
bohr, I met the following problem:

dstart -c -p(14:31:23) running dstart in single mode
Segmentation fault
13.207u 0.136s 0:13.62 97.8%0+0k 0+18312io 0pf+0w
error: command   /Users/wenhhu/wien2k14/dstartpara -c start.def   failed

Can anyone tell what is this error? And How can we solve it?

Best,
Wenhao
___
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



--
--
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
--
___
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

Re: [Wien] Graphene bandstructure

[Hajar Nejati]

I think that RKmax (case.in1) is one of the important computational parameters 
in an accurate describing of the electronic structure of graphene. I think that 
RKmax equal to 8.0 leads to a better band structure result for graphene.
All the best
 

  From: "Islam, Md F" 
 To: A Mailing list for WIEN2k users  
 Sent: Tuesday, December 22, 2015 7:21 PM
 Subject: [Wien] Graphene bandstructure
   
Hi,

    I am trying to do a bandstructure calculation of graphene to check if I can
reproduce results discussed in literature (I am using a unit cell of 2 atoms). 
With spin-orbit coupling, there should be a gap of the order of few micro-eV
and without spin-orbit, there should not be any gap at Dirac point. But I am 
getting a gap of meV even without spin-orbit. I tried both GGA and LDA with 
very dense mesh but the gap does not close. So I am wondering if anyone 
have any suggestion about how to do it in Wien2k.


Thanks,
Fhokrul
___
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


  ___
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

Re: [Wien] Graphene bandstructure

[Islam, Md F]

Thanks, for your reply. I have used a vacuum of 30 bohr but I can 
try with larger vacuum to check if it makes any difference.


Fhokrul



From: wien-boun...@zeus.theochem.tuwien.ac.at 
[wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of 
t...@theochem.tuwien.ac.at [t...@theochem.tuwien.ac.at]
Sent: Tuesday, December 22, 2015 10:20 AM
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] Graphene bandstructure

Hi,

For graphene, you need to add vacuum in the z-direction in order to
avoid interactions between the periodically repeated monolayers.
Maybe the vacuum that you used is not large enough.

F. Tran

On Tue, 22 Dec 2015, Islam, Md F wrote:

> Hi,
>
> I am trying to do a bandstructure calculation of graphene to check if I 
> can
> reproduce results discussed in literature (I am using a unit cell of 2 atoms).
> With spin-orbit coupling, there should be a gap of the order of few micro-eV
> and without spin-orbit, there should not be any gap at Dirac point. But I am
> getting a gap of meV even without spin-orbit. I tried both GGA and LDA with
> very dense mesh but the gap does not close. So I am wondering if anyone
> have any suggestion about how to do it in Wien2k.
>
>
> Thanks,
> Fhokrul
> ___
> 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
>
___
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
___
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

Re: [Wien] case.qtlup/dn files were empty

[Elias Assmann]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA256

On 12/21/2015 06:51 PM, venkatesh chandragiri wrote:
> I have done parallel SCF calculations in a cluster (the
> case.vector_* files are created in a separate scratch folder) and
> later I was copied the entire folder into a local computer due to
> memory issues at cluster. After some days, I was copied the entire
> folder into cluster (the same case.vector_* files are also copied
> into scratch folder into the cluster ). Although, the x lapw2
> -up/-dn -qtl -c -p runs smoothly without error (writing shell
> script for generating .machines file), the case.qtlup/dn files does
> not contain any data (0 bytes). Kindly, let me know the possible
> error in the present DOS calculation.

I do not know what would cause that, but note that `x lapw2 -qtl' is
not itself parallelized; `-p' means only “read parallel vector files”.
 This means you do not need `.machines'.  On the other hand, it reads
`.processes' to see how many vector files there should be, so if you
deleted that, that might have caused the error.

> I also tired to run the "x lapw2 -up/-dn -qtl -c -p " by keeping
> all the case.vector_* files into same parent folder. This gives
> also give error without running x lapw2. But, this error is
> connected to location of case.vector_* files which is not seen the
> earlier run.

You probably need to `set SCRATCH=./' in this case.  Include the error
messages next time.


Elias

-BEGIN PGP SIGNATURE-
Version: GnuPG v2
Comment: Using GnuPG with Icedove - http://www.enigmail.net/

iQIcBAEBCAAGBQJWeRahAAoJEE/4gtQZfOqPKH8P/0xjS1Oh3N1VZO6AQ6Kia0a/
KiSSulv3B2+8wGpsVJHI30xl1RhSF2llZCaEBXHLGX/rHadNxyVILMVcWvfr/ba0
Sl0L3Aa1FzrLVVZJOIO62tQWPQc6MwLmE8fios4uZUb/tOxYdpzH/omzLpyDt8A3
HIMPhOm8fsIWB3o+9x/d6S48G//zs7JujLCmwwiH3BB4qcYJd3yV5Q8tNo4FVGdP
wL/FvdGobLCVPU6QYI/dq4q3Uho6SGrJC0f+cgZkw+8G0AVhf2ISRzFlgbMaqJqQ
iYphe7hReaxiH3UIKO1LDYIZSif1X7N18Im5V+BUrErg8GRmGwFy7a/MiwWT51Ok
McFOOXl7RiyVJQglty9TuLNnIKa4lXdnMxHaGRIMSO8ppEVnlca47Sitlxy45JxJ
qeGEEa9bwaK9sqRjjO22Pwn7Lqew8Ds4f/s60mBbYb0vdbvHPM+W60ybQOJRQ3o4
QUCZ58HuuNfSbgPACx2WRLE69wgGSCkU+Ll0KiEhGbkQhjS61NyyAK1kjVPv9Ywy
qecv/Y7xURfibwMWpYymDajLTAgI21vsmZyZg3vfAxqKn1xg0yZW5l3uh9XHi9lI
DS7F4o8m+x/XOtfqyYQBA6yNvmQHItZxZUOJ5qvQWGDbpT+ZdCJ4yh2VUkmV8Y0D
XPStXYHeEj9tNeSWtddt
=Aqg5
-END PGP SIGNATURE-
___
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

[Wien] Graphene bandstructure

[Islam, Md F]

Hi,

 I am trying to do a bandstructure calculation of graphene to check if I can
reproduce results discussed in literature (I am using a unit cell of 2 atoms). 
With spin-orbit coupling, there should be a gap of the order of few micro-eV
and without spin-orbit, there should not be any gap at Dirac point. But I am 
getting a gap of meV even without spin-orbit. I tried both GGA and LDA with 
very dense mesh but the gap does not close. So I am wondering if anyone 
have any suggestion about how to do it in Wien2k.


Thanks,
Fhokrul
___
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

Re: [Wien] Graphene bandstructure

[tran]

Hi,

For graphene, you need to add vacuum in the z-direction in order to
avoid interactions between the periodically repeated monolayers.
Maybe the vacuum that you used is not large enough.

F. Tran

On Tue, 22 Dec 2015, Islam, Md F wrote:


Hi,

I am trying to do a bandstructure calculation of graphene to check if I can
reproduce results discussed in literature (I am using a unit cell of 2 atoms).
With spin-orbit coupling, there should be a gap of the order of few micro-eV
and without spin-orbit, there should not be any gap at Dirac point. But I am
getting a gap of meV even without spin-orbit. I tried both GGA and LDA with
very dense mesh but the gap does not close. So I am wondering if anyone
have any suggestion about how to do it in Wien2k.


Thanks,
Fhokrul
___
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


___
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

Re: [Wien] Formula full-potential

[tran]

Hi,

I was wrong, since there is no detail on the construction of the potential
in Dufek's thesis. To my knowledge, there is unfortunately no document
where the construction of the potential is explained in great details
specifically for WIEN2k. This is not trivial and made more complicated by
the use of cubic harmonics for cubic symmetry. Also, in the interstitial
there is the concept of stars which is used for the Fourier coefficients.

A few more links to documents which may be helpful depending on what you
want to know in particular:

http://scitation.aip.org/content/aip/journal/jmp/22/11/10.1063/1.524800
http://journals.aps.org/prb/abstract/10.1103/PhysRevB.26.4571

Actually, for which reason do you need details of the potential?

F. Tran

On Mon, 14 Dec 2015, Tuan Vu wrote:



Dear Prof. F. Tran


The links on the site, we did not find detailed information on the construction 
and use of the full-potential in the
code WIEN2k. As you can see the thesis P. Dufek, you mentioned?

We will be very grateful, if you send us this thesis, even in hard copy at:

Russian Federation, Rostov-on-Dou, pl. Gagarin 1, Don State University, the 
department of "Electrical and
Electronics".

 

Kind Regards

Doctor of physical and mathematical sciences, Prof. Lavrentyev A.A. and PhD 
Student Tuan Vu


___
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

[Wien] wien2k workshop 2016

[Peter Blaha]

Dear WIEN2k users,

We are happy to announce the WIEN2k workshop for 2016. It will be held at:

  McMaster University, Hamilton, Canada
  4. - 7. June 2016

and hosted by O. Rubel (who contributed the BerryPI package to WIEN2k).

The 23rd workshop in the history of the WIEN code is a hands-on activity 
dedicated to teach the use of the WIEN2k Density Functional Theory 
Package. WIEN2k is one of the most popular electronic structure codes 
used to perform calculations with the Full Potential LAPW method. The 
workshop is a unique opportunity to learn the use, power and limitations 
of the package with the tutoring of the authors and developers of the 
code. The activities will be aimed at graduate students and researchers 
from industry and academia. The only pre-requisite is to have a basic 
knowledge of solid state physics and chemistry. It is planned as a 
four-day activity with lectures on the scientific aspects of the method, 
applications and hands-on activities on selected examples. It is a 
unique opportunity to receive a head start on a personal project.


You can present a Poster of your current work and in addition this 
workshop is coupled to the  28th Canadian Material Science Conference 
(http://cmscconf.org/; from 7. - 11. June 2016) which could be of 
interest for you too.


Hamilton can be reached easily from Toronto, where International flights 
are available to many countrys worldwide.


The registration cost is CND $550 (about USD $400 ) and covers Lunches, 
Coffee breaks and the social event, which will be an exciting excursion 
to the Niagara Falls!


More information and registration at:

   http://mcmasteel.mcmaster.ca/conf/index.html


I also wish you all a merry Christmas and a happy new year.

Particular thanks to all of you, who helped to answer the many questions 
on the mailing list.


PS: I'd appreciate if you enter your WIEN2k publications into 
www.wien2k.at/papers


--

  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
--
___
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

Re: [Wien] Graphene bandstructure

[Peter Blaha]

Graphene is metallic by "symmetry", i.e. EF is at a 2-fold eigenvalue at 
the K-point and bands cross with a linear dispersion.


From where do you know that graphene has a gap in your calculations ??

From :gap in the scf file or from plotting the bandstructure or ...

It the state at K is not degenerate, you have the wrong symmetry and are 
not doing graphene.


Am 22.12.2015 um 16:51 schrieb Islam, Md F:

Hi,

  I am trying to do a bandstructure calculation of graphene to check if I 
can
reproduce results discussed in literature (I am using a unit cell of 2 atoms).
With spin-orbit coupling, there should be a gap of the order of few micro-eV
and without spin-orbit, there should not be any gap at Dirac point. But I am
getting a gap of meV even without spin-orbit. I tried both GGA and LDA with
very dense mesh but the gap does not close. So I am wondering if anyone
have any suggestion about how to do it in Wien2k.


Thanks,
Fhokrul
___
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



--
--
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
--
___
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

Re: [Wien] Graphene bandstructure

[Michael Sluydts]

While I haven't done any graphene calculations, one of the typical 
issues in bandgap discrepancies is also the existence of strain. Ensure 
your lateral lattice parameters are optimized using your current 
functional so that you're certain you are looking at the band structure 
of the energetic minimum. Of course don't optimize the vacuum or you'll 
end up with graphite...


Best regards,

Michael Sluydts

Op 22/12/2015 om 17:43 schreef Islam, Md F:

Thanks, for your reply. I have used a vacuum of 30 bohr but I can
try with larger vacuum to check if it makes any difference.


Fhokrul



From: wien-boun...@zeus.theochem.tuwien.ac.at 
[wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of 
t...@theochem.tuwien.ac.at [t...@theochem.tuwien.ac.at]
Sent: Tuesday, December 22, 2015 10:20 AM
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] Graphene bandstructure

Hi,

For graphene, you need to add vacuum in the z-direction in order to
avoid interactions between the periodically repeated monolayers.
Maybe the vacuum that you used is not large enough.

F. Tran

On Tue, 22 Dec 2015, Islam, Md F wrote:


Hi,

 I am trying to do a bandstructure calculation of graphene to check if I can
reproduce results discussed in literature (I am using a unit cell of 2 atoms).
With spin-orbit coupling, there should be a gap of the order of few micro-eV
and without spin-orbit, there should not be any gap at Dirac point. But I am
getting a gap of meV even without spin-orbit. I tried both GGA and LDA with
very dense mesh but the gap does not close. So I am wondering if anyone
have any suggestion about how to do it in Wien2k.


Thanks,
Fhokrul
___
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


___
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
___
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



--
ir. Michael Sluydts
Center for Molecular Modeling
Ghent University
Technologiepark 903
9052 Zwijnaarde, Belgium
tel. +32 (0)9 264 66 19
https://molmod.ugent.be

___
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

Re: [Wien] Graphene bandstructure

[Islam, Md F]

Hi Michael,

Thanks for your comments. You may be right. I haven't relaxed lateral
lattice parameters, just used the experimental values. 

Best regards,
Fhokrul

 


From: wien-boun...@zeus.theochem.tuwien.ac.at 
[wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of Michael Sluydts 
[michael.sluy...@ugent.be]
Sent: Tuesday, December 22, 2015 11:10 AM
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] Graphene bandstructure

While I haven't done any graphene calculations, one of the typical
issues in bandgap discrepancies is also the existence of strain. Ensure
your lateral lattice parameters are optimized using your current
functional so that you're certain you are looking at the band structure
of the energetic minimum. Of course don't optimize the vacuum or you'll
end up with graphite...

Best regards,

Michael Sluydts

Op 22/12/2015 om 17:43 schreef Islam, Md F:
> Thanks, for your reply. I have used a vacuum of 30 bohr but I can
> try with larger vacuum to check if it makes any difference.
>
>
> Fhokrul
>
>
> 
> From: wien-boun...@zeus.theochem.tuwien.ac.at 
> [wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of 
> t...@theochem.tuwien.ac.at [t...@theochem.tuwien.ac.at]
> Sent: Tuesday, December 22, 2015 10:20 AM
> To: A Mailing list for WIEN2k users
> Subject: Re: [Wien] Graphene bandstructure
>
> Hi,
>
> For graphene, you need to add vacuum in the z-direction in order to
> avoid interactions between the periodically repeated monolayers.
> Maybe the vacuum that you used is not large enough.
>
> F. Tran
>
> On Tue, 22 Dec 2015, Islam, Md F wrote:
>
>> Hi,
>>
>>  I am trying to do a bandstructure calculation of graphene to check if I 
>> can
>> reproduce results discussed in literature (I am using a unit cell of 2 
>> atoms).
>> With spin-orbit coupling, there should be a gap of the order of few micro-eV
>> and without spin-orbit, there should not be any gap at Dirac point. But I am
>> getting a gap of meV even without spin-orbit. I tried both GGA and LDA with
>> very dense mesh but the gap does not close. So I am wondering if anyone
>> have any suggestion about how to do it in Wien2k.
>>
>>
>> Thanks,
>> Fhokrul
>> ___
>> 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
>>
> ___
> 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
> ___
> 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


--
ir. Michael Sluydts
Center for Molecular Modeling
Ghent University
Technologiepark 903
9052 Zwijnaarde, Belgium
tel. +32 (0)9 264 66 19
https://molmod.ugent.be

___
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
___
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

Re: [Wien] Graphene bandstructure

[Islam, Md F]

Hi,

   Thanks for your suggestion. I have checked up to RKmax=9 but the gap
didn't close. But I was using GGA xc functional. I will try with LDA if it 
makes 
any difference. I read in some paper, LDA is supposed to be used for these 
calculations.  


Regards,
Fhokrul




From: wien-boun...@zeus.theochem.tuwien.ac.at 
[wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of Hajar Nejati 
[hajar.nejatip...@yahoo.com]
Sent: Tuesday, December 22, 2015 11:46 AM
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] Graphene bandstructure

I think that RKmax (case.in1) is one of the important computational parameters 
in an accurate describing of the electronic structure of graphene. I think that 
RKmax equal to 8.0 leads to a better band structure result for graphene.

All the best




From: "Islam, Md F" 
To: A Mailing list for WIEN2k users 
Sent: Tuesday, December 22, 2015 7:21 PM
Subject: [Wien] Graphene bandstructure

Hi,

I am trying to do a bandstructure calculation of graphene to check if I can
reproduce results discussed in literature (I am using a unit cell of 2 atoms).
With spin-orbit coupling, there should be a gap of the order of few micro-eV
and without spin-orbit, there should not be any gap at Dirac point. But I am
getting a gap of meV even without spin-orbit. I tried both GGA and LDA with
very dense mesh but the gap does not close. So I am wondering if anyone
have any suggestion about how to do it in Wien2k.


Thanks,
Fhokrul

___
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


___
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