[Pw_forum] Help: About spin-polarization

[Jia Chen]

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
>
>
>
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>


-- 
Jia Chen

Dept of Chemistry
Princeton University
Princeton, NJ 08544
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