[Pw_forum] SOC+Magnetization in bilayer heterostructures: Impossible to converge

[David Soriano]

Hi,


I am trying to converge a SCF calculation of a bilayer structure with SOC and magnetic V: MoSe2/VSe2. See the input file below:


&CONTROL
                 calculation = 'scf' ,
/
&SYSTEM
                       ibrav = 0
                   celldm(1) = 1.0 ,
                         nat = 6 ,
                         ntyp = 3 ,
                  ecutwfc = 60.0,
                 occupations = 'smearing' ,
                     degauss = 0.001 ,
                     lspinorb = .true.,
                     noncolin = .true.,
                     starting_magnetization(1) = 0.001D0,
/
&ELECTRONS
        mixing_mode = 'local-TF' ,
/
&IONS
/
&CELL
/
CELL_PARAMETERS alat
   5.437914144   3.152910164  -0.003742247
   5.437914144  -3.152910164  -0.003742247
  -0.033355109   0.000000000  43.886125527
ATOMIC_SPECIES
   V   1.000000   V.rel-pbe-spn-kjpaw_psl.0.2.3.UPF
   Mo  1.000000   Mo.rel-pbe-spn-kjpaw_psl.0.3.0.UPF
   Se  1.000000   Se.rel-pbe-n-kjpaw_psl.0.2.UPF
ATOMIC_POSITIONS angstrom
V       -0.014505031   0.000000000   0.289175199
Se       1.913587627   0.000000000   1.854706939
Se       1.910003017   0.000000000  -1.304783106
Mo       1.916933515   0.000000000   6.724381364
Se       3.838132355   0.000000000   8.379171699
Se       3.835939653   0.000000000   5.070743199
K_POINTS automatic
   1 1 1   0 0 0


The iteration steps look like:


     total magnetization       =     0.00     0.98     0.00 Bohr mag/cell
     absolute magnetization    =   847.77 Bohr mag/cell


The calculations are done in a single k-point just for testing. Anything changes even increasing the k-mesh to 8 8 1. The pseudopotentials seem not to be affecting the result, since the same calculation with US ones gives me similar giant "absolute magnetization". Two important observations are:


(1) The same calculation for the monolayers (namely, only MoSe2 or VSe2) converge perfectly.

(2) Increasing ecutwfc and ecutrho the absolute magnetization decreases but still gives values of the order of 100 Bohr mag/cell


Any help on this will be welcome!


Thanks.

Best ,

David.


Dr. David Soriano
International Iberian Nanotechnology Lab - INL
Av. Mestre José Veiga s/n
4715-330 Braga
Portugal
Phone (INL): +351 253 140 112 Ext. 2378
Phone (mobile): +34 645 766 938


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