[Pw_forum] about perovskite and AuCu3

[Duy Le]

It should be cubic perovskite. So
Primitive vectors  are:
a 0 0
0 a 0
0 0 a
and coordinates of atoms are:
0. 0. 0. (Au)
0.5 0.5 0. (Cu)
0.0 0.5 0.5 (Cu)
0.5 0.0 0.5 (Cu)
--------------------------------------------------
Duy Le
PhD Student
Department of Physics
University of Central Florida.

"Men don't need hand to do things"


On Wed, Feb 23, 2011 at 5:35 AM, kangbugy at lycos.co.kr
<kangbugy at lycos.co.kr>wrote:

>  Hi.
> I study QE as graduate student in Korea.
> But I have many problems.
> One of them is about AuCu3 structure.
> This basic structure is perovskite, but there is not a atom at body center.
>
> i.e., it is fcc structure.
> Because I thought fcc structure, I used that 'ibrav = 2'.
> Also,
> atomic position is
>  Au 0.00 0.00 0.00
>  Cu 0.50 0.50 0.00
> But scf.out's result appeared that 'atomic position #1 and #2 are overlap'.
> I don't understand that.
>
> Another question is scf data of perovskite.
> What can I input the data about perovskite?
>
>  &SYSTEM
>                        ibrav = 1,
>                            A = 3.717 ,
>                            B = 3.717 ,
>                            C = 3.717 ,
>                        cosAB = 90 ,
>                        cosAC = 90 ,
>                        cosBC = 90 ,
>                          nat = 5,
>                         ntyp = 3,
>                      ecutwfc = 30,
>  /
>  &electrons
>  /
> ATOMIC_SPECIES
>  Mg 24.305 Mg.pz-n-vbc.UPF
>    C 16.01 C.pz-rrkjus.UPF
>  Ni 58.71  Ni.pz-nd-rrkjus.UPF
>
> ATOMIC_POSITIONS
>  Mg 0.00 0.00 0.00
>    C 0.50 0.50 0.50
>  Ni 0.00 0.50 0.50
>  Ni 0.50 0.50 0.00
>  Ni 0.50 0.00 0.50
>
> K_POINTS automatic
>  10 10 10 0 0 0
>
> Help me please.
>
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>
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