[Pw_forum] Symmetry problem in Ge and phonon calculation problem in InP
Stefano de Gironcoli
degironc at sissa.it
Wed Mar 31 23:30:11 CEST 2010
dear Ashutosh Kumar,
the LO-TO splitting comes from macroscopic electric fields that build up
in the cell of polar materials.
however you are using occupations='smearing' which is appropriate for
metals where no electric field can be calculated.
remove the occupation='smearing' bit so that the code knows you are
woking with an insulator.
stefano
Ashutosh Kumar wrote:
> Sorry, I forgot to write the error I was getting. With InP, it says
> task # 0
> from phq_readin : error # 1
> no elec. field with metals
>
> with q=0. I tried the example02 for Si and C, and it worked fine, but in InP, it keeps on saying above.
>
> Extremely sorry for writing again the symmetry problem in Ge. I searched the forum about germanium and read many of those results, but could not find anything, so I wrote the problem here.
>
>
> Ashutosh Kumar
> Grad Student
> The Ohio State University
>
> ________________________________________
> From: pw_forum-bounces at pwscf.org [pw_forum-bounces at pwscf.org] on behalf of pw_forum-request at pwscf.org [pw_forum-request at pwscf.org]
> Sent: Wednesday, March 31, 2010 2:28 PM
> To: pw_forum at pwscf.org
> Subject: Pw_forum Digest, Vol 33, Issue 83
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> Today's Topics:
>
> 1. Symmetry problem in Ge and phonon calculation problem in InP
> (Ashutosh Kumar)
> 2. Re: (no subject) (Gabriele Sclauzero)
> 3. about xcrysden (Shaptrishi Sharma)
> 4. Re: phonon dispersion for graphene (Elie Moujaes)
> 5. Re: phonon dispersion for graphene (Paolo Giannozzi)
> 6. Re: Symmetry problem in Ge and phonon calculation problem in
> InP (Paolo Giannozzi)
> 7. Re: problems with Ta2O5 compound (Paolo Giannozzi)
> 8. Re: hi (Paolo Giannozzi)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 31 Mar 2010 15:49:02 +0000
> From: Ashutosh Kumar <kumar.198 at buckeyemail.osu.edu>
> Subject: [Pw_forum] Symmetry problem in Ge and phonon calculation
> problem in InP
> To: "pw_forum at pwscf.org" <pw_forum at pwscf.org>
> Message-ID:
> <6D7E0C0F56302745BD0EC910BF4FF30813FB0201 at BL2PRD0103MB037.prod.exchangelabs.com>
>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Dear pwscf users
>
> I've been trying to do phonon calculations, for elemental and compound semiconductors(Si, Ge, InP and SiC). Si and Ge both have exactly the same structure and space group, so symmetry operations are also same. Below is the self consistent input file, i'm using. In case of Si and Ge, the scf.out file works with all the 48 symmetry operations but in case of Ge it rejects all the inversion symmetry opertors. Also, for further calculations i'm using exactly the procedure given in example07 directory.
>
> Also, for InP, I used the same procedure, but i'm missing the splitting of phonon spectra at higher frequency, as reported in publications. After going through the forums, I got to know that I should use zasr=.true. and epsil=.true. for calculations in InP, since it is a polar semiconductor. I tried this and the phonon calculation job keeps on crashing. I don't understand what should I do to solve this problem?
>
>
> &control
> calculation='scf'
> restart_mode='from_scratch',
> prefix='ge',
> pseudo_dir = '/nfs/18/osu5465/espresso/espresso-3.2/pseudo/',
> outdir='/nfs/18/osu5465/espresso/tmp/'
> /
> &system
> ibrav= 2, celldm(1) =10.691, nat=2 , ntyp= 1,
> ecutwfc =25.0,
> occupations='smearing', smearing='methfessel-paxton', degauss=0.05,
> /
> &electrons
> conv_thr = 1.0d-8
> mixing_beta = 0.7
> /
> ATOMIC_SPECIES
> Ge 72.61 Ge.pz-bhs.UPF
> ATOMIC_POSITIONS {crystal}
> Ge 0.250000 0.250000 0.25000000
> Ge 0.000000 0.000000 0.00000000
> K_POINTS {automatic}
> 8 8 8 0 0 0
>
> --
> Ashutosh Kumar
> Grad Student
> The Ohio State University
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> ------------------------------
>
> Message: 2
> Date: Wed, 31 Mar 2010 17:59:08 +0200
> From: Gabriele Sclauzero <sclauzer at sissa.it>
> Subject: Re: [Pw_forum] (no subject)
> To: PWSCF Forum <pw_forum at pwscf.org>
> Message-ID: <4BB3714C.9080109 at sissa.it>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> sylvia mueni wrote:
>
>> hi im working on the latice constants of BaF2. I have a problem in determining the
>> atomic positions of the hexagonal phase. please help
>>
>
> Which kind of problem?
>
> GS
>
> P.S. please specify your affiliation. Thanks!
>
>
>> thanks, sylvia
>>
>>
>>
>>
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________ Pw_forum mailing list
>> Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum
>>
>
> --
>
>
> o ------------------------------------------------ o
> | Gabriele Sclauzero, PhD Student |
> | c/o: SISSA & CNR-INFM Democritos, |
> | via Beirut 2-4, 34014 Trieste (Italy) |
> | email: sclauzer at sissa.it |
> | phone: +39 040 3787 511 |
> | skype: gurlonotturno |
> o ------------------------------------------------ o
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 31 Mar 2010 17:12:56 +0100
> From: Shaptrishi Sharma <sh.shapt at gmail.com>
> Subject: [Pw_forum] about xcrysden
> To: pw_forum at pwscf.org
> Message-ID:
> <j2ta8a0c4081003310912ja99b91b5vd10b645460b11338 at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi there,
>
> I am not much familar with xcrysden. I wanted to make a supercell in
> xcrysden with a certain cell_parametrs (in put file of scf calculation in
> quantum espresso), but on going to option 'Modify' and then try to draw the
> number of units to 3 along y and z axis. It shows me that certain number of
> atoms are being deleted. I have checked the cell_parameter by changing the
> cell_parameter , but not much help. Kindly help !
> Thanks
>
> Shaptarishi
>
> Msc (Physics)
> Pune
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> Message: 4
> Date: Wed, 31 Mar 2010 18:40:10 +0100
> From: Elie Moujaes <elie.moujaes at hotmail.co.uk>
> Subject: Re: [Pw_forum] phonon dispersion for graphene
> To: <pw_forum at pwscf.org>
> Message-ID: <SNT114-W5535D5628F735BE0382F62D31E0 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
>
>
> Thanks very much for your reply. What if I want to plot the graph of frequency versus the wavevector K specifying the Gamma, K and M points..Can one do this in one go or does he have to calculate the frequencies for each of the points separately and then connect them.
>
>
>
> N.B: I was trying to use ldisp=true and provide an nq1 x nq2 x nq3 grid and I got the previous error. Any examples dealing with this?
>
>
>
>
>
> Thanks
>
>
>
> Elie Mouaes
>
> University of Nottingham
>
> NG7 2RD
>
> UK
>
>
>> Date: Wed, 31 Mar 2010 17:16:57 +0200
>> From: nnlinh at sissa.it
>> To: pw_forum at pwscf.org
>> Subject: Re: [Pw_forum] phonon dispersion for graphene
>>
>> Your input file lacks the points where you want to calculate phonon
>> dispersion (Gamma, X, ...)
>> So, you should see in example02 for reference of phonon input file
>>
>> Good luck
>> Linh
>>
>> Elie Moujaes wrote:
>>
>>> Sear PWSCF users,
>>>
>>> I am calculating the phonon dispersion for graphene. I did the scf
>>> calculations then when I am running the ph.x command, I always get the
>>> error:
>>>
>>>
>>>
>>> Program PHONON v.4.1.2 starts ...
>>> Today is 31Mar2010 at 12: 1:50
>>>
>>> Ultrasoft (Vanderbilt) Pseudopotentials
>>>
>>> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>>> from phq_readin : error # 1
>>> reading inputph namelist
>>> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>>>
>>> stopping ...
>>>
>>>
>>>
>>>
>>> which means that something is wrong in the input. But I could not fins
>>> any mistake in the input file...Can anyone please check it for me? My
>>> input is:
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> &inputph
>>>
>>> tr2_ph=1.0d-14,
>>>
>>> prefix='ph mono graphene',
>>>
>>> ldisp=.true.,
>>>
>>> nq1=28, nq2=28, nq3=1,
>>>
>>> amass(1)=12.00000,
>>>
>>> outdir='/tmp/results_MOUJAES/',
>>>
>>> fildyn='phmgraphene.dyn'
>>>
>>> /
>>>
>>>
>>>
>>> Thanks
>>>
>>>
>>>
>>> Elie Moujaes
>>>
>>> University of Nottingham
>>>
>>> NG7 2RD
>>>
>>> UK
>>>
>>>
>>>
>>>
>>>
>>>
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>> --
>> -----------------------------------------------------
>> Nguyen Ngoc Linh, PhD Student
>> c/o: SISSA & CNR-INFM Democritos,
>> via Beirut 2-4, 34014 Trieste (Italy)
>> email: nnlinh at sissa.it
>> phone: +39 04 03787 319
>> skype: ngoclinh84phys
>> -----------------------------------------------------
>> "The physics is theoretical but the fun is real"
>>
>>
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> Message: 5
> Date: Wed, 31 Mar 2010 19:52:37 +0200
> From: Paolo Giannozzi <giannozz at democritos.it>
> Subject: Re: [Pw_forum] phonon dispersion for graphene
> To: PWSCF Forum <pw_forum at pwscf.org>
> Message-ID: <A8AC1F4B-8966-45DE-BC4E-8991A5DCF8E9 at democritos.it>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>
>
> On Mar 31, 2010, at 19:40 , Elie Moujaes wrote:
>
>
>> N.B: I was trying to use ldisp=true and provide an nq1 x nq2 x nq3
>> grid and I got the previous error. Any examples dealing with this?
>>
>
> examples/example06
>
> ---
> Paolo Giannozzi, Dept of Physics, University of Udine
> via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
>
>
> ------------------------------
>
> Message: 6
> Date: Wed, 31 Mar 2010 20:04:05 +0200
> From: Paolo Giannozzi <giannozz at democritos.it>
> Subject: Re: [Pw_forum] Symmetry problem in Ge and phonon calculation
> problem in InP
> To: PWSCF Forum <pw_forum at pwscf.org>
> Message-ID: <EC8CE1AB-745D-499C-B4FE-F2EDF5F72DF2 at democritos.it>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>
>
> On Mar 31, 2010, at 17:49 , Ashutosh Kumar wrote:
>
>
>> In case of Si and Ge, the scf.out file works with all the 48
>> symmetry operations
>> but in case of Ge it rejects all the inversion symmetry opertors.
>>
>
> congratulations! this is the 1000000th time somebody reports this.
> You win the
> right to write parallel symmetrization in G-space for the phonon
> code. Once you
> have done this, Ge will no longer reject any symmetry operation.
>
> By the way, is Ge in the first row different from Ge in the second?
>
>
>> I tried this and the phonon calculation job keeps on crashing
>>
>
> crashing how? If it crashes for a good reason, the reason is printed
> on output.
> If it crashes for no apparent reason: consider that many compilers
> miscompile
> the phonon code.
>
> P.
> ---
> Paolo Giannozzi, Dept of Physics, University of Udine
> via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
>
>
> ------------------------------
>
> Message: 7
> Date: Wed, 31 Mar 2010 20:21:41 +0200
> From: Paolo Giannozzi <giannozz at democritos.it>
> Subject: Re: [Pw_forum] problems with Ta2O5 compound
> To: PWSCF Forum <pw_forum at pwscf.org>
> Message-ID: <F56577F0-9448-47C8-885C-C68662D0F7D9 at democritos.it>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>
> On Mar 31, 2010, at 10:37 , Maxim Ivanov wrote:
>
>> First of all energy gap is too small
>>
>>
> this is a well known problem of DFT
>
>> Moreover I have not find defect level in 14, 42, 168 atoms
>> supercells with oxygen vacancy in the center of the cell.
>>
>>
> oxides are notoriously nasty stuff, in which sometimes you don't get
> things right
>
>> Ta has 3 d electrons and is described by ultrasoft pseudopotential.
>> I took it from pwscf.org. It might be problem in the potential.
>>
>>
> why should the problem be in the pseudopotential? any evidence, or
> any other
> calculations to compare with?
>
> P.
> ---
> Paolo Giannozzi, Dept of Physics, University of Udine
> via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
>
>
> ------------------------------
>
> Message: 8
> Date: Wed, 31 Mar 2010 20:28:15 +0200
> From: Paolo Giannozzi <giannozz at democritos.it>
> Subject: Re: [Pw_forum] hi
> To: PWSCF Forum <pw_forum at pwscf.org>
> Message-ID: <4F276755-9D2E-4B92-B564-40DCABDA6616 at democritos.it>
> Content-Type: text/plain; charset=US-ASCII; format=flowed
>
>
> On Mar 31, 2010, at 10:15 , Thaneshwor Kaloni wrote:
>
>
>> I am unable to get the seedname.eig file
>>
>
> I guess you may get more help from the Wannier mailing list:
> http://www.wannier.org/forum.html
>
> P.
> ---
> Paolo Giannozzi, Dept of Physics, University of Udine
> via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
>
>
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>
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