[Pw_forum] Re: Help generating Pd pseudo

[stewart at cnf.cornell.edu]

Hi Lucas, 

   Palladium has a high magnetic susceptibility and sits right on the edge 
of magnetism.  I have been looking at nanostructures based on Pd and I have 
found that the pseudopotential choice is very crucial in determining whether 
you get the correct non-magnetic fcc ground state.  All pseudopotentials 
predict that as you expand the palladium lattice, you should see a 
transition to a magnetic state. 

However, of the four pseudopotentials available on the PWscf website, only 
the Perdew-Zunger (LDA) with non-linear core correction and the semi-core d 
valence state (Pd.pz-nd-rrkjus.UPF) gives the correct non-magnetic fcc 
ground state.  All varieties of GGA psp predict a ground magnetic state, 
most likely due to the fact that they slightly overestimate the lattice 
constant.  This problem is something that has been observed over a wide 
range of codes including Siesta, VASP, and Wien2k.  See the comment by S. 
Alexendre et al., PRL 96 079701 (2006) for more details. 

For your calculations, I would suggest including non-collinear core 
corrections and seeing if this helps. 

Best regards, 

Derek
 


Lucas Fernandez Seivane writes: 

> Hi to all in the list 
> 
> I am trying to generate a fully relativistic pseudo for Pd. But with
> these parameters I always get magnetic Pd! Do you see anything wrong
> in the input? 
> 
> 
> Best wishes to all
> Lucas Fernández Seivane
> Ph.D. student, Universidad de Oviedo, Spain 
> 
>  &input
>         title='Pd',
>         zed=46.0,
>         rel=2,
>         iswitch=3,
>         rlderiv=2.50,
>         eminld=-3.0,
>         emaxld=3.0,
>         deld=0.02,
>         nld=5,
>         config='[Kr] 4d9 5s1 5p0',
>         dft='LDA'
>  /
>  &inputp
>         pseudotype=3,
>         lloc=0,
>         file_pseudopw='PdrelNN.RRKJ3',
>         nlcc=.false.
>  /
> 7
> 4D  3  2  4.00  0.00  1.80  2.40  1.50
> 4D  3  2  0.00 -0.20  1.80  2.40  1.50
> 4D  3  2  5.00  0.00  1.80  2.40  2.50
> 4D  3  2  0.00 -0.20  1.80  2.40  2.50
> 5P  2  1  0.00  0.00  2.40  2.40  0.50
> 5P  2  1  0.00 -0.00  2.40  2.40  1.50
> 5S  1  0  1.00  0.00  2.40  2.40  0.50
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################################
Derek Stewart, Ph. D.
Scientific Computation Associate
250 Duffield Hall
Cornell Nanoscale Facility (CNF)
Ithaca, NY 14853
stewart (at) cnf.cornell.edu
(607) 255-2856