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[Martin Fuchs <fuchs@FHI-Berlin.mpg.de>]

Hello,

there exist some reference data for fhi98pp pseudopotentias
for Ga with 3d's as valence or core electrons:

M. Fuchs, J.L.F. Da Silva, C. Stampfl, J. Neugebauer, and
M. Scheffler, Cohesive properties of group-III nitrides: A
comparative study of all-electron and pseudopotential
calculations using the generalized gradient approximation
(13 pages). Phys. Rev. B 65, 245212 (2002).

Basically, the fhipp allows to build an f potential into the Ga
with 3d as valence, that can be used as local potential
and performed in quite good accordance with all-electron
calculations, unlike the more common choice of the s as
local. Your preference might depend a bit on what you want:
good agreement e.g. with expt. structure or good agreement
with reference (all-electron) DFT calculations.

I have such potentials, with the usual editing they should
be readily usable with abinit. If you like, I can send them
to you.

Best wishes
Martin Fuchs

Thomas Maxisch wrote:

> Dear Michel,
>
> Thanks for the quick answer.
>
> >I recently did some calculations for GaAs and I had to generated a Ga
> >pseudo with 3d electrons. I copy below my notes on this problem. I can
> >send you the pseudo to your personal address, I don't want to fill
> >everyone mailbox unnecessary.
>
> Thanks a lot. A stupid question: With 3d electrons as core or as valence
> electrons. This is not clear for me with your description. I need them as
> valence in order to have reasonable results for GaN calculations.
>
> The ghost states of Ga are known and there are different ways to overcome
> them. Our way to do that is to include the empty f orbitals into the
> pseudopotential and make them local. The resulting potential is very good
> in the sense of electronic properties. Nevertheless the lattice constant is
> also not as good as it should be (10.435 a.u.) Unfortunately up to my
> knowledge the only program who converges for this configuration is the
> program of J.L. Martins. And I haven't had the time until now to write a
> routine to make them readable by abinit.
>
> But I have not yet tested this configuration with the fhi98pp code. I thing
> that it is worth to try it.
> I think that I will try something in this direction the next days with the
> fhi98pp.
> Why have you also modified the As potential?
>
> When the 3d are as valence electrons in your potential, it woul be very
> nice if you can send me the Ga potential to my personal address.
>
> Thanks a lot,
> Thomas
>
> ----------------
>
> >lattice parameter for GaAs
> >--------------------------
> >
> >31ga.pspnc                TM pseudo (s,p, local=p) (from the Abinit web 
> >page)
> >31-Ga:tm.fhi              TM pseudo (s,p,d, local=p) (generated by me with
> >fhi98pp)
> >31-Ga:tm_with_core.fhi    TM pseudo (s,p,d, local=p, with partial core)
> >(generated by me with fhi98pp)
> >33as.pspnc                TM pseudo (s,p) (from the Abinit web page)
> >33-As:tm.fhi              TM pseudo (s,p,d, local=p) (generated by me with
> >fhi98pp)
> >
> >GaAs_tm_from_Abinit_web_page.out         Optimazation of the lattice
> >parameter with pseudo 31ga.pspnc and 33
> >as.pspnc
> >GaAs_fhi_tm_Ga_with_core_As_no_core.out  Optimazation of the lattice
> >parameter with pseudo 31-Ga:tm_with_cor
> >e.fhi and 33-As:tm.fhi
> >
> >When I use the TM pseudopotentials of the Abinit web page for Ga and
> >As (31ga.pspnc, 33as.pspnc), I had a large error in the lattice
> >parameter (opt at 10.29726 a.u. compare with exp at 10.677 (Kittel),
> >3.6% error). I then notice that these peudo did not have a d
> >component. I generated new pseudopotentials with the code fhi98pp
> >including the d component (pseudo 31-Ga:tm.fhi and 33-As:tm.fhi). I
> >had some problems (ghost state) when I use the local d for ga so i put
> >both local at p. This improved the lattice to about 10.45. I then
> >included partial core charge for the Ga (31-Ga:tm_with_core.fhi). With
> >this pseudo and 33-As:tm.fhi for the As, the optizimed lattice is
> >10.56888 a.u. so the error now is 1.01% which is acceptable.
>
> --
> __________________________________________________________________________
> Thomas Maxisch                          | Tel  : +41 (0) 21 693 45 16
> EPFL FSB-ITP                            | Fax  : +41 (0) 21 693 44 44
> PHB-Ecublens, CH-1015 Lausanne          | Email : Thomas.Maxisch@epfl.ch
> __________________________________________________________________________

--
Martin Fuchs
Fritz-Haber-Institut der MPG
Faradayweg 4-6
14195 Berlin
Germany
Phone: +30 8413 4802
Fax:     +30 8413 4701
E-Mail: fuchs@fhi-berlin.mpg.de