How to calculate with the LDA+U ( AFM, FM, NM )

How to calculate with the LDA+U

To apply the LDA+U there are two steps to follow:

1/ Calculate the U parameter
2/ Apply the LDA+U

Note: For the beginners, they shall start with the second step as follows:

* Create two files named: case.inorb, case.indm ( In case of complex calculation we need the file case.indmc instead of case.indm ) from the SCR templates in wien2k manually

* We can start with NiO example with d orbitals

* Here the two files for NiO: ( we use the antiferromagnetic structure with two atoms Ni1 and Ni2)

* The calculation is done with spin-polarized case






------------------ top of file: case.indm --------------------
-9.                       Emin cutoff energy
2                         number of atoms for which density matrix is calculated
1  1  2                  index of 1st atom, number of L's, L1
2  1  2                  index of 2nd atom, number of L's, L1
0 0                   r-index, (l,s)-index
------------------- bottom of file ------------------------

For the non magnetic or ferromagnetic (spin-polarized ) calculations where we have one atom Ni the two files will be as follows:


---------------- top of file: case.inorb --------------------
1  1  0                        nmod, natorb, ipr
PRATT,1.0                      mixmod, amix
1 1 2                          iatom nlorb, lorb
1                              nsic (LDA+U(SIC) used)
0.52 0.0                       U J

---------------- bottom of file:  --------------------


------------------ top of file: case.indm --------------------
-9.                         Emin cutoff energy
1                           number of atoms for which density matrix is calculated
1  1  2                   index of 1st atom, number of L's, L1
0 0                       r-index, (l,s)-index
------------------- bottom of file ------------------------

NOTE :  

If you want to force a non-magnetic solution you can constrain the spin-polarization to zero using runsp_c_lapw.