[Pw_forum] Problems Computing Cholesky for VC-Relax of MnO2

[Lorenzo Paulatto]

On 06/09/17 21:01, Lance Kavalsky wrote:
> I am no longer getting the error after increasing the energy cutoff of 
> the wavefunctions to 250.0 Ry, decreasing the smearing to 0.01, and 
> resetting the diagonalization back to davidson.


You mean of the charge density cutoff?

> I have experimented with varying the starting magnetizations and it 
> consistently converges to a non-magnetic state. However, M. Kan et al. 
> showed that a ferromagnetic state should exist via DFT (J. Phys. Chem. 
> Lett., *2013*, /4/ (20), pp 3382–3386). Is this lack of magnetic states 
> in my investigations more likely a result of not yet discovering a 
> suitable starting magnetization, or could there be another reason such 
> as choice of pseudopotentials?
> 
I do not know your system, but you may have to start with to different 
species of Mg, in order to break symmetry. This is necessary if one of 
the symmetries of your crystal send Mg1 to Mg2 changing its orientation.

Example:

      nat=4, ntyp=3,
...
    starting_magnetization(1)=0.5 !Mn1
    starting_magnetization(2)=0.5 !Mn2
    starting_magnetization(3)=-0.5 !Oxygen
...
  ATOMIC_SPECIES
   Mn1 54.9380  Mn.pbe-spn-kjpaw_psl.0.3.1.upf
   Mn2 54.9380  Mn.pbe-spn-kjpaw_psl.0.3.1.upf
   O  15.9994  O.pbe-n-kjpaw_psl.0.1.upf

ATOMIC_POSITIONS {angstrom}
Mn1       1.463698094   2.529784343   0.000006382
Mn2       2.923484801   0.001355102   1.898036230
O        0.003938199   1.686984261   0.949009435
O        1.463753969   0.844151693   2.847056902


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-- 
Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
phone: +33 (0)1 442 79822 / skype: paulatz
www:   http://www-int.impmc.upmc.fr/~paulatto/
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