[Pw_forum] anti-ferromagnetic calculations

[Eyvaz Isaev]

Hi,

> I did the calculation with ibrav = 1 and 8 atoms

In order to reduce atoms number involved in AFM calculations for B1 type 
structure (FeO, NiO) you can use basis vectors and atomic positions from 
run_example  file  from example25

Bests,
Eyvaz.
-------------------------------------------------------------------
Prof. Eyvaz Isaev, 
Department of Physics, Chemistry, and Biology (IFM), Linkoping University, 
Sweden 

Theoretical Physics Department, Moscow State Institute of Steel & Alloys, 
Russia, 

isaev at ifm.liu.se, eyvaz_isaev at yahoo.com




________________________________
From: mohnish pandey <mohnish.iitk at gmail.com>
To: PWSCF Forum <pw_forum at pwscf.org>
Sent: Thu, January 13, 2011 2:11:29 PM
Subject: Re: [Pw_forum] anti-ferromagnetic calculations

Dear Padmaja!
                            As I am using the latest version of QE(i.e 4.2) the 
'nelup' and "neldw" variables are no longer there anymore. For magnetic 
calculations starting with some initial magnetization i.e. 
starting_magnetization(i). In my experience with AF calculations you should have 
even number of atoms in the unitcell( unless the system is frustrated or 
something like that). I did the calculation for NiO which have rocksalt 
structure so there will be 2 atoms in the unit cell with ibrav = 2. But with 
this I was not able to hit the ground state because there was only one Ni. So 
the number mag/unitcell was not zero. But when I did the calculation with ibrav 
= 1 and 8 atoms the total magnetization~0 and I am able to reach the ground 
state. And as also Shrubha pointed out that you must do Lowdin analysis to see 
the magnetization and check the up and down spins. 
I hope it helps.


On Thu, Jan 13, 2011 at 11:25 AM, Padmaja Patnaik <padmaja_patnaik at yahoo.co.uk> 
wrote:

Dear All
>
>For an anti-ferromagnetic calculation to run in QE which of the following way is 
>more correct.
>1. specify different values of starting magnetization for different atoms in the 
>compound. I mean one positive and one negative value.
>
>2. specifying the nelup and neldown.
>
>Thanks and regards
>Padmaja Patnaik
>Research Scholar
>Dept of Physics
>IIT Bombay
>Mumbai, India 
>
>_______________________________________________
>Pw_forum mailing list
>Pw_forum at pwscf.org
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>
>


-- 
Regards,
MOHNISH,
-----------------------------------------------------------------
Mohnish Pandey
Y6927262,5th Year dual degree student,
Department of Chemical Engineering,
IIT KANPUR, UP, INDIA
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