[Pw_forum] Help: About spin-polarization

[Giuseppe Mattioli]

Dear Huazhong Liu
Flicking through some literature...? Excess electrons in TiO2 (bulk, surface, nanostructures, ...) 
are one of the most investigated issues in theoretical (and experimental) condensed matter, physical 
chemistry, surface chemistry, environmental science, ..., papers.
I avoid to cite papers of mine (noblesse oblige), but you can find many papers by Annabella Selloni 
and Elio Pacchioni which should be quite interesting...
HTH
Giuseppe


On Friday 18 May 2012 08:53:24 Jia Chen wrote:
> Hi Huazhong,
> 
> Only problem I can spot is that the smearing is a little bit too large.
> Room temperature is only 23meV, degauss = 0.002Ry would be more reasonable.
> I guess the situation is that the single electron should be a d state of
> Ti, but PBE functional makes it a delocalized state and the system becomes
> metallic, then big smearing completely eliminates magnetization... Just my
> guess...
> 
> On Thu, May 17, 2012 at 9:58 PM, Huazhong Liu <huazhorg at 163.com> wrote:
> > Dear all,
> > 
> >      I have got a problem of spin-polarization calculation. I put one H
> > 
> > atom onto the stoichiometric TiO2 surface. I think that is must have
> > magnetic properties after I optimized the adsorption system. But I didn't
> > find the magnetism in the system after the calculation. Here are the
> > parameters which set for spin-polarization calculation:
> > ...................
> > 
> >  /
> >  &system
> >  
> >     ibrav=..........
> >     nat=49  , ntyp=3,
> >     nspin=2,
> >     starting_magnetization(1)= 0.5
> >     starting_magnetization(2)= 0.5
> >     starting_magnetization(3)= 0.5
> >     ecutwfc=30.0,
> >     ecutrho=300.0,
> >     occupations='smearing', smearing='gauss', degauss=0.02,
> >  
> >  /
> > 
> > ATOMIC_SPECIES
> > 
> >  Ti   47.867       Ti.pbe-sp-van_ak.UPF
> >  O    15.9994      O.pbe-van_ak.UPF
> >  H    1.00794      H.pbe-van_ak.UPF
> > 
> > ...........................
> > 
> > I got the result as below:
> >       The total energy is the sum of the following terms:
> >      one-electron contribution =  -12795.07240972 Ry
> >      hartree contribution      =    6472.21004247 Ry
> >      xc contribution           =    -456.66736582 Ry
> >      ewald contribution        =    3879.97911645 Ry
> >      smearing contrib. (-TS)   =      -0.01329486 Ry
> >      
> >      total magnetization       =     0.00 Bohr mag/cell
> >      absolute magnetization    =     0.00 Bohr mag/cell
> >  
> >  convergence has been achieved in  10 iterations
> > 
> > ..................................
> > 
> > Will you please find any problem in my parameters? Why I can not get the
> > magnetism of the system?  Thank you!
> > 
> > regards,
> > Huazhong Liu
> > 
> > 
> > 
> > _______________________________________________
> > Pw_forum mailing list
> > Pw_forum at pwscf.org
> > http://www.democritos.it/mailman/listinfo/pw_forum

-- 
********************************************************
- Article premier - Les hommes naissent et demeurent
libres et ègaux en droits. Les distinctions sociales
ne peuvent être fondèes que sur l'utilitè commune
- Article 2 - Le but de toute association politique
est la conservation des droits naturels et 
imprescriptibles de l'homme. Ces droits sont la libertè,
la propriètè, la sùretè et la rèsistance à l'oppression.
********************************************************

   Giuseppe Mattioli                            
   CNR - ISTITUTO DI STRUTTURA DELLA MATERIA   
   v. Salaria Km 29,300 - C.P. 10                
   I 00015 - Monterotondo Stazione (RM)          
   Tel + 39 06 90672836 - Fax +39 06 90672316    
   E-mail: <giuseppe.mattioli at ism.cnr.it>