[QE-users] Fw: Problem with SOC

[Guido Menichetti]

Dear Kostov

First of all, please add your signature (affiliation/university/position)

About the difference between SP and SOC calculation:
The magnetism in SOC calculation in non-collinear so if you give to the
code just the magnitude of the magnetic moments it could not be enough to
reach the right/desired magnetic configuration. If you look for a specific
magnetic configuration you could also try the "constrained magnetization".
Try to add a guess on the starting angles (of the magnetic moments)

About the  vc-relax: It could happen if the relaxed structure is far from
the starting one.
Are you in the same magnetic configuration?
Try the relaxation again.

HTH
Best
G.

Il giorno sab 2 nov 2019 alle ore 03:31 David Kostov <dkca at yahoo.com> ha
scritto:

> I am still waiting for a reply for this issue. Thank you in advance.
>
>
>
>
>
> ----- Forwarded Message -----
> *From:* David Kostov <dkca at yahoo.com>
> *To:* Quantum ESPRESSO Users Forum <users at lists.quantum-espresso.org>
> *Sent:* Wednesday, October 30, 2019, 2:43:25 p.m. CST
> *Subject:* Problem with SOC
>
> Dear QE community
>
> I want to study my FM system with and without SOC included. Thus I tried
> geometry optimization, vc-relax, for the two cases.
>
> In the FM without SOC, I got the following magnetization. In my system,
> there are two magnetic atoms. So I think one atom will have 6.48/2= 3.24
> Bohr mag/cell.
>
>   total magnetization       =     6.37 Bohr mag/cell
>   absolute magnetization    =     6.48 Bohr mag/cell
>
>
> However, in the FM+SOC, the magnetization results for the final structure
> in the vc-relax process is zero.
>
> total magnetization       =    -0.00    -0.00     0.00 Bohr mag/cell
> absolute magnetization    =     0.00 Bohr mag/cell
>
>
> I am little bit not clear with this situation. Can someone please clarify
> me what this results tells me  in the FM+SOC case ? (is this converging to
> a NM case? I mean since absolute mag=0?)
>
> But in the input script, I defined in a way the system is FM.
>
> input in the FM+SOC
> .................................
>
>  &SYSTEM
>     nat = 6,
>     ntyp = 2,
>     degauss = 0.12,
>     ibrav = 0,
>     ecutwfc = 140,
>      nbnd=50,
>     occupations = 'smearing',
>     smearing = 'mp',
>     starting_magnetization(1)=0.1,
>     starting_magnetization(2)=0.0,
>     noncolin= .true.
>     lspinorb= .true.
>
> ............................................................................................
>
>
>
> The other problem I am facing is when I check the scf calculation with the
> converged final lattice and atomic coordinates (of course with the same
> input SYSTEM data above), the pressure is very high at the end, around
> 40GPa. I m not sure what is wrong with the calculation.
>
> Thank you in advance
>
> D.
>
>
>
>
>
>
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-- 
***************************************

Guido Menichetti
Post-Doc researcher in Condensed matter physics
Istituto Italiano di Tecnologia
Theory and technology of 2D materials
Address: Via Morego, 30, 16163 Genova
Email:  guido.menichetti at iit.it
             guido.menichetti at df.unipi.it
             menichetti.guido at gmail.com

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