[Pw_forum] Pseudopotential for indium

Pascal Boulet pascal.boulet at univ-amu.fr
Thu Dec 7 14:23:17 CET 2017


Dear Nicola,

You are right I also noticed that the ‘pseudo' state energies match very well the AE ones. 

Regarding the alloys Vegard’s law should hold according to experimental data. We are indeed using supercells.

I am currently running tests on pure indium. As mentioned by Paolo, the mass is irrelevant in the results for static calculations (as expected!). I have preliminary results with relativistic+SO calculation that are a bit better:
3.0786 x 3.0786 x 5.0095

Recall: 
exp.: 3.2449 x 3.2449 x 4.9420
previous calc.: 3.2168 x 3.2168 x 5.3095

This is obtained with Ecut=50 Ry Ecutrho=500 Ry, 8x8x8 kpts=40 kpts
With these parameters c improves substantially (1.4% off) but a and c worsen a bit (5% off).

I am running a test with more kpts first. In a second step I will increase Ecut and Ecutrho and will report to the forum.

Pascal







Pascal Boulet
—
Professor in computational chemistry - DEPARTEMENT OF CHEMISTRY
Aix-Marseille University - ST JEROME - Avenue Escadrille Normandie Niemen - F-13013 Marseille - FRANCE
Tél: +33(0)4 13 55 18 10 - Fax : +33(0)4 13 55 18 50
Site : http://madirel.univ-amu.fr/pages_web_BOULET_PASCAL/infos - Email : pascal.boulet at univ-amu.fr




Le 6 déc. 2017 à 23:24, Nicola Marzari <nicola.marzari at epfl.ch> a écrit :

> 
> Dear Pascal,
> 
> 
> the comparison with all-electron calculations looks good to me - see
> here for tests and for the other pseudos:
> http://materialscloud.org/sssp/results/In_conv_patt.png
> 
> Comparing with expts is more delicate -  c/a with PBE is
> quite a bit off e.g. in ferroelectric perovskites.
> 
> Re the alloy, how are you constructing the intermediate concentrations?
> Supercells? (Vegard law should hold)
> 
> nicola
> 
> On 06/12/2017 23:03, Paolo Giannozzi wrote:
>> You mean: the value 49.0 here?
>> ATOMIC_SPECIES
>> In 49.0 In.pbe-dn-kjpaw_psl.1.0.0.UPF
>> Iit is used only by molecular dynamics, not by structural optimization.
>> 
>> I don't remember In to be an especially nasty element, at least for 
>> simple III-V compounds like InAs. I would examine the effect of a denser 
>> k-point grid, and of spin-orbit
>> 
>> Paolo
>> 
>> 
>> On Wed, Dec 6, 2017 at 10:46 PM, Saif Ullah <kiterunner7 at gmail.com 
>> <mailto:kiterunner7 at gmail.com>> wrote:
>> 
>>    Dear Boulet,
>> 
>>    I think I found where the error is. You are using the atomic number
>>    of In instead of its atomic mass.
>> 
>>    Regards
>>    Saif
>>    Department of physics, UFJF, Brazil
>> 
>> 
>> 
>>    On Wed, Dec 6, 2017 at 6:45 PM, Pascal Boulet
>>    <pascal.boulet at univ-amu.fr <mailto:pascal.boulet at univ-amu.fr>> wrote:
>> 
>>        Thanks Lorenzo for the suggestion. I have tried with Ecut=120 Ry
>>        and Ecutrho=1200 Ry. I get a slightly better result (but c is
>>        still very bad):
>>        3.2168 x 3.2168 x 5.3095
>> 
>>        as compared with:
>>        exp.: 3.2449 x 3.2449 x 4.9420 angström
>>        previous calc.: 3.2715 x 3.2715 x 5.4541 angström
>> 
>> 
>>        Best,
>> 
>>        Pascal Boulet
>>>>        /Professor in computational chemistry - DEPARTEMENT OF CHEMISTRY/
>>        Aix-Marseille University - ST JEROME - Avenue Escadrille
>>        Normandie Niemen - F-13013 Marseille - FRANCE
>>        Tél: +33(0)4 13 55 18 10 <tel:+33%204%2013%2055%2018%2010> - Fax
>>        : +33(0)4 13 55 18 50 <tel:+33%204%2013%2055%2018%2050>
>>        Site : http://madirel.univ-amu.fr/pages_web_BOULET_PASCAL/infos
>>        <http://madirel.univ-amu.fr/pages_web_BOULET_PASCAL/infos> -
>>        Email : pascal.boulet at univ-amu.fr <mailto:pascal.boulet at univ-amu.fr>
>> 
>> 
>> 
>> 
>>        Le 6 déc. 2017 à 18:54, Lorenzo Paulatto <paulatz at gmail.com
>>        <mailto:paulatz at gmail.com>> a écrit :
>> 
>>>        Hello,
>>>        can you try with a much higher cutoff (100 Ry or more) and see
>>>        if the lattice parameter improves? I've noticed that sometimes
>>>        pslibrary pseudos are much a harder than they look, especially
>>>        when converging stress
>>> 
>>>        Cheers
>>> 
>>>        -- 
>>>        Lorenzo Paulatto
>>>        Written on a virtual keyboard with real fingers
>>> 
>>>        On Dec 6, 2017 18:32, "Pascal Boulet"
>>>        <pascal.boulet at univ-amu.fr <mailto:pascal.boulet at univ-amu.fr>>
>>>        wrote:
>>> 
>>>            Dear all,
>>> 
>>>            We are working on some In-containing semiconductors
>>>            M(1-x)In(x)L. M is supposed to be a smaller atom than In.
>>>            We are facing the problem that when we vary x from 0 to 1
>>>            the cell parameters is decreasing instead of increasing.
>>>            Although this may happen, it should not be the case here
>>>            since ‘pure’ ML has a smaller cell parameter than ‘pure’ InL.
>>> 
>>>            We have run some calculations on crystal indium using the
>>>            PSL library pseudo potentials (both PAW and USPP). one of
>>>            the calculated cell parameters are miles away from the
>>>            experimental ones:
>>>            exp.: 3.2449 x 3.2449 x 4.9420 angström
>>>            calc.: 3.2715 x 3.2715 x 5.4541 angström
>>> 
>>>            Does anyone have tested the In pseudo potentials of the
>>>            PSL library or faced this problem with indium?
>>> 
>>>            Thank you for your help and time.
>>> 
>>>            Best regards
>>> 
>>>            PS1. here are some information from the input file:
>>> 
>>>             calculation    = 'vc-relax’,
>>>              etot_conv_thr  = 1d-7,
>>>              forc_conv_thr  = 5d-5,
>>>              ibrav          = 0,
>>>               nat            = 2,
>>>              ntyp           = 1,
>>>              ecutwfc        = 45.d0,
>>>              ecutrho        = 450.d0,
>>>              nbnd = 18
>>>            &ELECTRONS
>>>              conv_thr       = 1d-8,
>>>            &CELL
>>>              press_conv_thr = 0.01d0,
>>>              cell_factor    = 1.5,
>>>            ATOMIC_SPECIES
>>>            In 49.0 In.pbe-dn-kjpaw_psl.1.0.0.UPF
>>>            K_POINTS automatic
>>>            8 8 4 1 1 1
>>>            CELL_PARAMETERS angstroms
>>>            3.2449 0. 0.
>>>            0. 3.2449 0.
>>>            0. 0. 4.9420
>>>            ATOMIC_POSITIONS crystal
>>>                In           0.00000000    0.00000000    0.00000000
>>>                In           0.50000000    0.50000000    0.50000000
>>> 
>>>            PS2. And some from the output:
>>> 
>>>                bfgs converged in  18 scf cycles and  15 bfgs steps
>>>                 (criteria: energy <  1.0E-07 Ry, force <
>>>             5.0E-05Ry/Bohr, cell <  1.0E-02kbar)
>>>            CELL_PARAMETERS (angstrom)
>>>               3.271466870   0.000000000   0.000000000
>>>               0.000000000   3.271466870   0.000000000
>>>               0.000000000   0.000000000   5.454067219
>>>            !    total energy              =    -821.46750731 Ry
>>>            total   stress  (Ry/bohr**3)                   (kbar)    
>>>            P=    0.30
>>> 
>>>            Pascal Boulet
>>>>>>            /Professor in computational chemistry - DEPARTEMENT OF
>>>            CHEMISTRY/
>>>            Aix-Marseille University - ST JEROME - Avenue Escadrille
>>>            Normandie Niemen - F-13013 Marseille - FRANCE
>>>            Tél: +33(0)4 13 55 18 10 <tel:04%2013%2055%2018%2010> -
>>>            Fax : +33(0)4 13 55 18 50 <tel:04%2013%2055%2018%2050>
>>>            Site :
>>>            http://madirel.univ-amu.fr/pages_web_BOULET_PASCAL/infos
>>>            <http://madirel.univ-amu.fr/pages_web_BOULET_PASCAL/infos> -
>>>            Email : pascal.boulet at univ-amu.fr
>>>            <mailto:pascal.boulet at univ-amu.fr>
>>> 
>>> 
>>> 
>>> 
>>> 
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>> 
>> -- 
>> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>> Phone +39-0432-558216, fax +39-0432-558222
>> 
>> 
>> 
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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
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