[Pw_forum] Quick question on Hartwigsen-Goedeker-Hutter pseudopotential

willy kohn willykohn at gmail.com
Thu Oct 2 22:54:43 CEST 2008


Hi, Axel:

Well, I didn't blame the PP, and I didn't mean to. My question is quite
simple. I was told that with a LDA PP, Ge has a vanishing or negative band
gap at Gamma point. But with this PP, it has a gap of 0.50 eV (using
experimental lattice) or 0.80 eV (after relaxation). I'm not sure what I
knew is correct, and that is the reason I wanted another PP to verify.

Best,

Wei



On Thu, Oct 2, 2008 at 2:12 PM, Axel Kohlmeyer
<akohlmey at cmm.chem.upenn.edu>wrote:

> On Thu, 2 Oct 2008, willy kohn wrote:
>
> WK> Hi, Axel:
> WK>
> WK> Thanks a lot for your quick answer. I need to do some calculations on
> some
> WK> compound semiconductors of Ge. But the PP (Ge.pz-bhs.UPF) provided in
> the
> WK> PWSCF website yeided some results that I don't understand. So I would
> like
>
> perhaps it would be useful to explain in more detail what
> is confusing you and what calculation you did with what input.
> perhaps some people here can comment on it. it is always easy
> to blame the pseudopotential (sometimes rightfully so), but
> more often than not, the real cause is in not doing a calculation
> correctly, or not using a pseudopotential correct.
>
> WK> to use some other PP's to check if I did the calculation correctly. Any
> WK> suggestions?
>
> i have a set of Ge pseudopotentials generated from parameters
> for a norm-conserving troullier-martins potential that is in
> the extended CPMD psp library. they have seen only very minimal
> transferability testing (using an atomic code in bessel basis),
> but so far seem to be ok, except for the OLYP one which has a
> ghost in the s-channel.
>
> i can send them to you in a private mail, if you are interested.
> no guarantees etc...
>
> cheers,
>   axel.
>
> WK>
> WK> Best,
> WK>
> WK> Wei
> WK>
> WK> On Thu, Oct 2, 2008 at 11:54 AM, Axel Kohlmeyer <
> akohlmey at cmm.chem.upenn.edu
> WK> > wrote:
> WK>
> WK> > On Thu, 2 Oct 2008, willy kohn wrote:
> WK> >
> WK> > WK> Dear PWSCF users:
> WK> > WK>
> WK> > WK> I have a quick question about using
> WK> > WK> Hartwigsen-Goedeker-Hutter<
> WK> >
> http://cvs.berlios.de/cgi-bin/viewcvs.cgi/cp2k/potentials/Goedecker/abinit/pade
> WK> > >pseudopotential
> WK> > WK> with PWSCF. Is there any converter to transfer the HGH pp
> WK> > WK> format to UPF used in PWSCF?
> WK> >
> WK> > none that i am aware of.
> WK> >
> WK> > the GTH pseudopotentials are analytical in real and reciprocal
> WK> > space and to incorporate them properly, one would have to do a
> WK> > lot of programming. in the CPMD code (from http://www.cpmd.org)
> WK> > they are treated as a special case, similar to ultra-soft psps.
> WK> >
> WK> > is there any particularly reason you'd need any of those?
> WK> >
> WK> > cheers,
> WK> >   axel.
> WK> >
> WK> >
> WK> > WK>
> WK> > WK> Best,
> WK> > WK>
> WK> > WK> Wei
> WK> > WK>
> WK> > WK> Georgia Tech
> WK> > WK>
> WK> >
> WK> > --
> WK> >
> =======================================================================
> WK> > Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu
> http://www.cmm.upenn.edu
> WK> >   Center for Molecular Modeling   --   University of Pennsylvania
> WK> > Department of Chemistry, 231 S.34th Street, Philadelphia, PA
> 19104-6323
> WK> > tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel:
> 1-215-898-5425
> WK> >
> =======================================================================
> WK> > If you make something idiot-proof, the universe creates a better
> idiot.
> WK> >
> WK>
>
> --
> =======================================================================
> Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
>   Center for Molecular Modeling   --   University of Pennsylvania
> Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
> tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
> =======================================================================
> If you make something idiot-proof, the universe creates a better idiot.
>
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