[Pw_forum] how to build cell for diamagnetic material?

[duchl06]

hi, thank you for the explanations.
 i read some book and found that the  diamagnetism is a normal, universal characteristic of the material, it is covered by other magnetism in non-diamagnetic materials.
 and some other told me that: paramagnetism is random orientation of spins throughout the material,
 Diamagnetism is local magnetic moment (no spins).So non spin-magnetisation calculation is indeed the closest thing to diamagnetism simulation.
Duy Le said  Diamagnetic materials are either AFM or FM, but there are diamagnetic materials, like Cu, Ag.
so, could I comprehend like this: 
 when do a calculation for AFM and FM materials, just do as Duy Le, Hui Wang and Paolo Giannozzi said.
 when do a calculation for DM materials or (paramagnetism)PM materials, just turn the spin polarized off?
 
 


graduate student: chen
xiaguanying university


在2009-10-02，"Duy Le" <ttduyle at gmail.com> 写道：
Oh, I see what you meant now. Diamagnetic materials are either AF or FM. Just do spin polarized calculation with starting_magnetization. I don't see any different between diamagnetic VS. AF/FM unless you have them in external magnetic file.


2009/10/1 xirainbow <nkxirainbow at gmail.com>
Dear Chen: 
You can use "   nspin = 2 ,   starting_magnetization(1) = 1.0,starting_magnetization(2) = -1.0,".
Then PWscf will change magnetization during scf or relaxation calculation.
If the start state is  antiferromagnetic state(zero initial magnetization), the scf result would be  zero magnetization(antiferromagnetic or paramagnetic).


2009/10/2 duchl06 <duchl06 at 163.com>

thanks every one's reply!
hi, Hui Wang
the example you supplied is a calculation for a antiferromagnetic material, i mean how to set the start magnetic moment for the diamagnetic material, 

 

best regards!



graduate student: chen
xiaguanying university



在2009-10-02，xirainbow <nkxirainbow at gmail.com> 写道： 

Dear Chen：


>  but i really donot know how to set up a cell for the diamagnetic material, and how to set >the start magnetic moment?





Hear is an example about graphene ribbon antiferromagnetic calculation.
Remember: different "starting_magnetization" atoms are treated as totally different atoms.



Input file:graphene.rx.in
&CONTROL
                 calculation = 'relax' ,
                  ..................
 /
 &SYSTEM
                       ibrav = 8,
                   celldm(1) = 4.67689278,
                   celldm(2) = 8.623989813,
                   celldm(3) = 4.048794087,
                    ....................
                         nat = 12,
                        ntyp = 2,
                       nspin = 2 ,
   starting_magnetization(1) = 1.0,
   starting_magnetization(2) = -1.0,
 /
 &ELECTRONS
             ...................
 /
 &IONS
             ....................
 /
ATOMIC_SPECIES
   C1   12.00000  C.pbe-rrkjus.UPF
   C2   12.00000  C.pbe-rrkjus.UPF
ATOMIC_POSITIONS crystal
   C1      0.000000000    0.236465542    0.000000000   
   C2      0.500000000    0.265456486    0.000000000   
   C1      0.500000000    0.334092417    0.000000000   
   C2      0.000000000    0.366772814    0.000000000   
   C1      0.000000000    0.433673757    0.000000000   
   C2      0.500000000    0.466640035    0.000000000   
   C1      0.500000000    0.533360168    0.000000000   
   C2      0.000000000    0.566326232    0.000000000   
   C1      0.000000000    0.633227130    0.000000000   
   C2      0.500000000    0.665907475    0.000000000   
   C1      0.500000000    0.734543349    0.000000000   
   C2      0.000000000    0.763534596    0.000000000   
K_POINTS automatic
  13 1 1   0 0 0



-- 
____________________________________
Hui Wang
School of physics, Nankai University, Tianjin, China




"中国制造",讲述中国60年往事

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____________________________________
Hui Wang
School of physics, Nankai University, Tianjin, China


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-- 
--------------------------------------------------
Duy Le
PhD Student
Department of Physics
University of Central Florida.
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