[Wien] (no subject)

Li, Zhiyuan zhiyuan.li at tmm.tu-darmstadt.de
Fri Feb 20 12:18:09 CET 2026 

Dear WIEN2k community and Prof. Blaha,


I am currently performing constrained DFT+U calculations on a 2x2x2 BaTiO3 supercell with an Fe dopant and an oxygen vacancy using WIEN2k 24.1. My ultimate goal is to systematically investigate all possible d-orbital electronic multiplets (following the methodology in Dorado et al., PRB 79, 235125 (2009) and previous discussions on this mailing list by Bin Shao in 2015 http://zeus.theochem.tuwien.ac.at/pipermail/wien/2015-July/023196.html and Jayangani in 2019 http://zeus.theochem.tuwien.ac.at/pipermail/wien/2019-July/029531.html).

The Core Issue:


I am observing a significant deviation (> 0.3 e-) between my explicitly constructed initial density matrix (.dmatup/dn), the IPDOS up to EF(Fe), and the final output density matrix obtained via lapwdm, even though the calculation converges successfully and i haven't released the constraint.

To test the constraint, I intentionally chose a non-standard configuration to ensure I can apply constraints beyond estimated egt2g spliting:

Target UP: Only dyz occupied (1.0)

Target DN: dxy, dz2, dxz, dx2-y2 occupied (1.0 each)

Here is a figure of the summary table of the discrepancies I observed:(with all smaller than 0.1 components ignored)
[cid:13df257c-eac1-40c4-98fd-36f12ca211db]
PS: I can only set d,dxy,dz2,dx2-y2,dxz+yz for this system in the qtl.

(I also considered the local rotation matrix, but since they share the same rotation and the tetragonal Ti site is not severely distorted, I believe it cannot fully explain this large deviation.)

Below are the full technical details of my setup. Any insights or suggestions on how to firmly "lock" these metastable states would be greatly appreciated.

My Questions:
large deviation while still constrained: I observe this huge discrepancy even before releasing the constraint. For example, my single dyz target was split into two ~0.85 occupations in .scfdmup. Does this imply that the system's symmetry is still actively forcing a degeneracy between xz and yz?

Normal behavior vs. Setup error: Is it normal to see such a large deviation between the setup .dmat and the output .scfdm while the orbital potential is still being actively applied, or does this indicate an error in my initialization/setup?

Physical/Algorithmic interpretation: If my setup is perfectly fine, how should I understand what is happening here? Is the imposed U potential simply not strong enough to overcome the hybridization and SCF mixing, thereby "washing out" my imposed constraint during the cycles?

Alternative methods for a "hard lock": Are there other techniques to more rigidly lock the desired electronic multiplet? For instance, should I artificially increase the $U$ value during the initial SCF cycles?

ALL Technical Details:

1. setup:
init_lapw -b -sp
prepare .indm &  .inorb & .dmatup/dn
x orb -up -p
x orb -dn -p
runsp_lapw -p -orbc -i 500 -ec 0.0001 -cc 0.001

2. .indm:

-12.                      Emin cutoff energy
 1                        number of atoms for which density matrix is calculated
 8  1  2      index of 1st atom, number of L's, L1
 0 0            r-index, (l,s)index

3. .inorb
1  1  0                      nmod, natorb, ipr
PRATT  1.0                     BROYD/PRATT, mixing
  8 1 2                          iatom nlorb, lorb
  1                              nsic 0..AMF, 1..SIC, 2..HFM
   0.37 0.07        U J (Ry)

4. initial .dmatup(target dyz)

   8 atom density matrix

    2  0.000000  0.000000  0.000000 L, Lx,Ly,Lz in global orthogonal system

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   1.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00

5. initial .dmatdn(target dxy, dz2, dxz, dx2-y2)
   8 atom density matrix

    2  0.000000  0.000000  0.000000 L, Lx,Ly,Lz in global orthogonal system

   1.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   1.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   1.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00   0.0000000000000E+00

   1.0000000000000E+00   0.0000000000000E+00

6. Post-processing for IPDOS up to EF:
x lapw2 -qtl -up -p
x lapw2 -qtl -dn -p
configure_int_lapw -b total 8 d,dz2,dxy,dx2y2,dxz+dyz
x tetra -up -p
x tetra -dn -p

UP (Target was only dyz = 1.0): d: 1.49108, dz2: 0.03198, dxy: 0.04066, dx2y2: 0.09713, dxz+dyz: 1.32129

DN (Target was dxy, dz2, dxz, dx2-y2 = 1.0 each): d: 3.70166, dz2: 0.72795, dxy: 0.82023, dx2y2: 1.30642, dxz+dyz: 0.84706

7. Post-processing for Output Density Matrix (lapwdm):
I used a .indmc file same to my .indm and ran:
x lapwdm -up -p
x lapwdm -dn -p

case.scfdmup (Target was dyz):
irtest           1           8   2.07000000000000
 Density matrix UPUP block, real part.  L= 2
         0.08807  0.00000  0.00000  0.00000  0.04017
         0.00000  0.85159  0.00000  0.00000  0.00000
         0.00000  0.00000  0.04101  0.00000  0.00000
         0.00000  0.00000  0.00000  0.85159  0.00000
         0.04017  0.00000  0.00000  0.00000  0.08807
...
:TRA008:  TRACE of UPUP MATRIX=   1.92035   0.00000

case.scfdmdn (Target was dxy, dz2, dxz, dx2-y2):
irtest           1           8   2.07000000000000
 Density matrix UPUP block, real part.  L= 2
         0.94475  0.00000  0.00000  0.00000  0.01576
         0.00000  0.48222  0.00000  0.00000  0.00000
         0.00000  0.00000  0.90325  0.00000  0.00000
         0.00000  0.00000  0.00000  0.48222  0.00000
         0.01576  0.00000  0.00000  0.00000  0.94475
...
:TRA008:  TRACE of UPUP MATRIX=   3.75719   0.00000


Thank you very much for your attention and time!

Best regards,
Zhiyuan Li

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