Dear All,
I am calculating the HartreeFock Selfenergy and Vxc contribution for GaN.
I am using a s2p1 pseudo for Ga and s2p3 for N.
I honestly do not understand why I get this "disordered" ordering of the states (from 5 to 10, in this case)
I would expect indeed that deeper states should have lower energy. But in my case 5th state at HF level has higher energy than the 6th (still at HF)
And moreover, the 8th state at LDA is my Valence Band and the 9th is my CB. Should I expect the energy difference between these two states corresponding to the bandgap (i.e, about 2.35 eV)
Thanks in advance,
my very best.
Giacomo
[xc] Functional Perdew & Zunger (xc)
XC HF and LDA [eV] @ K [1] (iku): 0.000 0.000 0.000
<5HF5> = 19.96117 .8670E8 <5LDA5> = 16.25794 .4089E8
<6HF6> = 20.25342 .1870E7 <6LDA6> = 16.98509 0.4142E8
<7HF7> = 20.34970 0.1262E8 <7LDA7> = 17.03668 0.1352E7
<8HF8> = 20.34970 0.9239E8 <8LDA8> = 17.03672 0.2222E8
<9HF9> = 8.991189 0.6053E9 <9LDA9> = 13.03069 0.4721E8
<10HF10> = 6.722379 0.1330E8 <10LDA10> = 11.55897 0.6082E9
<11HF11> = 7.562684 0.5999E9 <11LDA11> = 14.41783 .1089E7
<12HF12> = 4.280390 .7542E9 <12LDA12> = 9.997887 0.8340E9
Giacomo Giorgi, PhD.
The University of Tokyo.
wrong energy ordering???
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 myrta gruning
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Re: wrong energy ordering???
Dear Giacomo
What you reported are not the energies, but the matrix elements of the HartreeFock self energy <iHFi> and of the xc potential <iLDAi>.
They are ordered following the KS energies ordering coming out from the DFT calculations. The KS eneries are also reported in the r_* file, together with the LDA gap.
If you want you can get a perturbative HF energy for the state i by calculating:
E_HF^i = E_KS^i <iLDAi> + <iHFi>
those are not reported since HF does not give a good estimate for band gap anyway (far too large)
and this is just a step needed for getting the GW corrections.
I hope this clarifies things
Best
m
What you reported are not the energies, but the matrix elements of the HartreeFock self energy <iHFi> and of the xc potential <iLDAi>.
They are ordered following the KS energies ordering coming out from the DFT calculations. The KS eneries are also reported in the r_* file, together with the LDA gap.
If you want you can get a perturbative HF energy for the state i by calculating:
E_HF^i = E_KS^i <iLDAi> + <iHFi>
those are not reported since HF does not give a good estimate for band gap anyway (far too large)
and this is just a step needed for getting the GW corrections.
I hope this clarifies things
Best
m
Dr Myrta Grüning
Atomistic Simulation Centre
Queen's University Belfast  Northern Ireland
http://www.researcherid.com/rid/B15152009
Atomistic Simulation Centre
Queen's University Belfast  Northern Ireland
http://www.researcherid.com/rid/B15152009

 Posts: 14
 Joined: Tue Oct 06, 2009 9:36 am
Re: wrong energy ordering???
Dear Myrta,
it definitely clarifies all my doubts.
Thanks for the prompt and kind reply.
My best,
G
it definitely clarifies all my doubts.
Thanks for the prompt and kind reply.
My best,
G