[QE-users] Fw: Problem with SOC
Guido Menichetti
menichetti.guido at gmail.com
Tue Nov 5 12:01:08 CET 2019
Dear David
Did you try without constrained magnetization?
Are you sure that the ferromagnetic configuration with all spin parallel to
the x direction corresponds to the ground state?
The reason for high "constraint energy (Ryd)" could hide behind the choice
of the arrival state.
Re-Try the calculation without the constrained magnetization flag and Try
not to start with very highly symmetric configuration.
You can also study how the "constraint energy (Ryd)" varies as a function
of Lambda.
HTH
Best
Guido
Il giorno mar 5 nov 2019 alle ore 11:22 David Kostov <dkca at yahoo.com> ha
scritto:
> Dear Guido
>
> Thank you for your valuable comment. I tried your advises and could get
> the system get converged in the x direction magnetization with following
> options.
>
>
> &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,
> constrained_magnetization= 'atomic',
> angle1=90,
> angle2=0,
> noncolin= .true.
> lspinorb= .true.
> /
>
>
> However I have got to know from previous pw_forum's posts that with such a
> constrained calculation, the constrained energy in the convergence needs to
> be very close to zero. But in my case it is not. (last iteration in the
> vc-relaxed run copied below)
>
> total magnetization = 5.77 0.00 0.00 Bohr mag/cell
> absolute magnetization = 5.86 Bohr mag/cell
> lambda = 1.00 Ry
>
> iteration # 24 ecut= 140.00 Ry beta=0.30
> Davidson diagonalization with overlap
> ethr = 1.00E-13, avg # of iterations = 2.1
> constraint energy (Ryd) = 11.31368053
>
>
> Can you/someone else please let me know whether I can go forward with this
> configuration or it needs to change.
>
> I do not have any idea what to do to reduce constrained energy in this
> system, please advice me.
>
> Thank you
> David
> PhD student
> Okayama University
>
>
>
> On Saturday, November 2, 2019, 6:23:28 a.m. CST, Guido Menichetti <
> menichetti.guido at gmail.com> wrote:
>
>
> 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
>
> ****************************************
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
--
***************************************
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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