Losing magnetic moment in transiesta calculation

Asked by Yusuf Wicaksono on 2020-07-09

Dear Siesta Users/Developers,

I would like to ask for your kind help.

I did the Transiesta calculation to observe the in-plane transmission probability of graphene which is sandwiched with Ni cluster.
(the electrode that was used in the calculation is graphene while the scattering region contain graphene with Ni cluster in the middle).

At first, I did the SCF calculation for both electrode and scattering regions which the results showed the calculation was converged well.
From the converged SCF result of the scattering region, it is shown that the total spin moment is 38.00284 where this spin moment comes mainly from Nickel and this calculation is consistent with the similar calculation by using another DFT package.

After that, I calculated the transmission probability by using Transiesta.
The calculation was done without any error, but the result is strange.
The result showed the magnetic moment changed from 38.02365 to -0.07925 as follows.

        iscf Eharris(eV) E_KS(eV) FreeEng(eV) dDmax Ef(eV) dHmax(eV)
ts-scf: 1 3841187.562357 1080876.366557 1080876.366557 1.053714 -3.035461**********
     spin moment: S , {S} = 38.02365 0.0 0.0 38.02365
timer: Routine,Calls,Time,% = TS 1 142.597 4.95
ts-q: D E1 C1 E2 C2 dQ dQtot
ts-q: 0.002 22.961 -0.002 22.961 -0.002 -5.730E+2
ts-q: 0.002 23.000 -0.002 23.000 -0.002 -5.730E+2 -1.146E+3
ts-Vha: 0.38080E+03 eV
ts-scf: 2 16661506.118675 7430296.451844 7430296.451844 1.415916 -3.035461**********
     spin moment: S , {S} = -0.07925 0.0 0.0 -0.07925
ts-q: D E1 C1 E2 C2 dQ dQtot
ts-q: 0.026 22.961 -0.027 22.961 -0.027 -5.731E+2
ts-q: 0.026 23.000 -0.027 23.000 -0.027 -5.730E+2 -1.146E+3
ts-Vha: 0.38081E+03 eV
ts-scf: 3 7431651.565719 7430963.915622 7430963.915622 1.665982 -3.035461**********
     spin moment: S , {S} = -0.07925 0.0 0.0 -0.07925
ts-q: D E1 C1 E2 C2 dQ dQtot
ts-q: 0.002 22.961 -0.002 22.961 -0.002 -5.730E+2
ts-q: 0.002 23.000 -0.002 23.000 -0.002 -5.730E+2 -1.146E+3
ts-Vha: 0.38080E+03 eV
ts-scf: 4 7429608.532681 7430296.304936 7430296.304936 1.666117 -3.035461**********
     spin moment: S , {S} = -0.07925 0.0 0.0 -0.07925
mix: Pulay -- inversion failed, > SVD
ts-q: D E1 C1 E2 C2 dQ dQtot
ts-q: 0.001 22.961 -0.002 22.961 -0.002 -5.730E+2
ts-q: 0.001 23.000 -0.002 23.000 -0.002 -5.730E+2 -1.146E+3
ts-Vha: 0.38080E+03 eV

When I looked carefully into the output file, this strange result was produced because no electron occupied any of Nickel orbital for every Nickel atoms as follows

Species: Ni1
Atom Qatom Qorb
               3s 4s 4s 3py 3pz 3px 3dxy 3dyz
               3dz2 3dxz 3dx2-y2 3dxy 3dyz 3dz2 3dxz 3dx2-y2
               4Ppy 4Ppz 4Ppx
  13 0.000 0.000 -0.000 0.000 -0.000 -0.000 -0.000 0.000 0.000
              0.000 0.000 0.000 -0.000 -0.000 -0.000 -0.000 -0.000

              0.000 0.000 -0.000
  14 0.000 0.000 -0.000 0.000 -0.000 -0.000 -0.000 -0.000 0.000
              0.000 0.000 0.000 -0.000 -0.000 -0.000 -0.000 -0.000

              0.000 0.000 -0.000
  15 0.000 -0.000 0.000 0.000 -0.000 -0.000 0.000 -0.000 0.000
              0.000 0.000 -0.000 0.000 -0.000 -0.000 -0.000 0.000

              0.000 -0.000 -0.000
  16 0.000 0.000 0.000 0.000 -0.000 -0.000 -0.000 0.000 -0.000
             -0.000 0.000 -0.000 0.000 -0.000 -0.000 0.000 -0.000

              0.000 0.000 0.000
  17 -0.000 -0.000 0.000 -0.000 -0.000 -0.000 0.000 -0.000 0.000
              0.000 -0.000 -0.000 -0.000 -0.000 0.000 -0.000 -0.000

             -0.000 -0.000 0.000

Could you kindly help me to solve this problem? I appreciate your kind help.

Best,

Yusuf Wicaksono
Doctor Students
Department of Materials Science and Engineering
Osaka University

Question information

Language:
English Edit question
Status:
Solved
For:
Siesta Edit question
Assignee:
No assignee Edit question
Solved by:
Nick Papior
Solved:
2020-07-09
Last query:
2020-07-09
Last reply:
2020-07-09
Best Nick Papior (nickpapior) said : #1

To me this suggests that you have setup your device incorrectly.

Generally if you do a siesta and a transiesta @ 0 V you should find more or less the same charge density.

So please try and figure out if you setup the system correctly, read the manual for details. :)

Thanks Nick Papior, that solved my question.