[Wien] LDA+U calculations at with U at selected atoms

Tran, Fabien fabien.tran at tuwien.ac.at
Thu Dec 5 11:16:29 CET 2019


Hi,


After modification of case.inorb (don't forget to modify also case.indm(c)), it may be necessary to delete the vorb and dmat files:

rm case.vorb* case.dmat*

before restarting the calculation


F. Tran

________________________________
From: Wien <wien-bounces at zeus.theochem.tuwien.ac.at> on behalf of david yang <dyang2103 at gmail.com>
Sent: Thursday, December 5, 2019 10:39 AM
To: wien at zeus.theochem.tuwien.ac.at
Subject: [Wien] LDA+U calculations at with U at selected atoms

Dear Wien community,

I am performing LDA+U type calculation for SmCo5, and interested in look in the role of Co in generating large magnetic anisotropy for this materials.

(i)  First i ran a LDA+U calculation with U of 5 eV on Sm, with the following case.inorb file. Everything worked fine.

1  1  0                         nmod, natorb, ipr
PRATT  1.0                    BROYD/PRATT, mixing
1 1 3                          iatom nlorb, lorb
1                              nsic 0..AFM, 1..SIC, 2..HFM
0.367  0.00        U J (Ry)   Note: we recommend to use U_eff = U-J and J=0

(ii) then I included U of 3 eV at Co sites, in the following case.inorb input file. Everything worked fine.
1  6  0                         nmod, natorb, ipr
PRATT  1.0                    BROYD/PRATT, mixing
1 1 3                          iatom nlorb, lorb
2 1 2                          iatom nlorb, lorb
3 1 2                          iatom nlorb, lorb
4 1 2                          iatom nlorb, lorb
5 1 2                          iatom nlorb, lorb
6 1 2                          iatom nlorb, lorb
1                              nsic 0..AFM, 1..SIC, 2..HFM
0.367  0.00        U J (Ry)   Note: we recommend to use U_eff = U-J and J=0
0.220  0.00        U J (Ry)   Note: we recommend to use U_eff = U-J and J=0
0.220  0.00        U J (Ry)   Note: we recommend to use U_eff = U-J and J=0
0.220  0.00        U J (Ry)   Note: we recommend to use U_eff = U-J and J=0
0.220  0.00        U J (Ry)   Note: we recommend to use U_eff = U-J and J=0
0.220  0.00        U J (Ry)   Note: we recommend to use U_eff = U-J and J=0

(iii) At last I wanted to do a calculation with U just at Co site. I use the following case.inorb  input file:

1  5  0                         nmod, natorb, ipr
PRATT  1.0                    BROYD/PRATT, mixing
2 1 2                          iatom nlorb, lorb
3 1 2                          iatom nlorb, lorb
4 1 2                          iatom nlorb, lorb
5 1 2                          iatom nlorb, lorb
6 1 2                          iatom nlorb, lorb
1                              nsic 0..AFM, 1..SIC, 2..HFM
0.220  0.00        U J (Ry)   Note: we recommend to use U_eff = U-J and J=0
0.220  0.00        U J (Ry)   Note: we recommend to use U_eff = U-J and J=0
0.220  0.00        U J (Ry)   Note: we recommend to use U_eff = U-J and J=0
0.220  0.00        U J (Ry)   Note: we recommend to use U_eff = U-J and J=0
0.220  0.00        U J (Ry)   Note: we recommend to use U_eff = U-J and J=0

This run HOWEVER gives an error in case.outputorbup/dn file



 Conflict in atom indexes: iatom           2 ne jatom           1



This will works if I put U = 0eV at Sm in step (2). But before proceeding I wanted to clarify the following

(I) Is this expected behavior ?

(II) If I put a U of 0 eV at Sm, will that mimic a calculation with U only at Co site?


I can make this work by swapping the atom (putting the Co first) in the structure files, but then I will have to restart the entire run.

Your suggestions and thoughts are much appreciated.

Thanks in advance.


Regards,
David Yang
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