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

[Stefano de Gironcoli]

I don't know the details of the generation of  this particular PP but in 
the old good times there has been a very detailed comparison of LDA band 
structure calculation of Ge and GaAs between the PP method and LMTO [GB 
Bachelet and NE Christensen, Phys.Rev.B 31, 879 (1985) ].
The main result is that in order to get the correct (bad) gap in Ge and 
GaAs  1) scalar relativistic, 2) spin-orbit coupling, 3) 3d-state relaxation
are important... not to mention convergence w.r.t. to cutoff ...

Hope  this helps,

 Stefano de Gironcoli - SISSA and DEMOCRITOS

willy kohn wrote:
> 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 <mailto: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 <mailto: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
>     <mailto: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
>     <mailto: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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