[Pw_forum] magnetic moments in graphene with single vacancy :: discrepancy

[Paolo Giannozzi]

Based on your data, it looks like the discrepancy is between
FLEUR and the rest of the world

P.

On Fri, 2013-05-10 at 15:28 +0200, Martin Gmitra wrote:
> Dear all,
> 
> 
> I did some calculations for induced magnetism in graphene due to
> single vacancy (sometimes reffered as V1(5-9))
> using USPP (C.pbe-van_ak.UPF; ecutwfc=30, ecutrho=160) and NCPP
> (C.pbe-mt_fhi.UPF, ecutwfc=35, ecutrho=140).
> Calculations of relaxed structure give magnetic moment in the
> supercell of about 0.65 \mu_B in both the PP cases.
> However, I did calculations of the same structure using full-potential
> LAPW code FLEUR where the magnetic moment 
> (spin_up - spin_down) drops to value of 0.12256. There are also
> studies where similar structures have been studied 
> with SIESTA code:
> depending of supercell size from 1.1 to 1.5 \mu_B [Yazyev et al, Phys
> Rev B 75, 125408]
> Normconserving PPs give about 1.2 \mu_B
> [http://arxiv.org/abs/1006.0589]
> GIPAW gives 1.53 \mu_B
> [http://www.researchgate.net/publication/235566299_Non-collinear_magnetic_moments_in_graphene_with_vacancies]
> 
> 
> It seems that USPP and NCPP could not be the reason for the
> discrepancy, or?
> Could you comment please on the origin of the discrepancies between QE
> and LAPW?
> 
> 
> Best regards,
> 
> 
> Martin Gmitra
> Uni Regensburg, Germany
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-- 
Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222