[Wien] Calculation of properties by wien2k for other than zero K

[Peter Blaha]

"nonmagnetic" is a sloppy term.  ferromagnetic, disordered, paramagnetic or diamagnetic
is much more precise.

A "ferromagnetic" material usually does NOT loose its LOCAL magnetic moment above
Tc, but the moments are no longer long range ordered, but get disordered.

Thus in most cases even above Tc a "ferromagnetic" calculation is a much better
approximation than a "nonmagnetic" one !!

The best you could do, is to create a large supercell, put some moments on each
atom with "random" spin-up/dn orientation such that the total moment of the cell
is zero. This corresponds to a "disordered local moment" model of a ferromagnetic
solid above Tc.

In addition you may select TEMPerature broadening with the appropriate temperature.

>                             I have a basic question regarding the 
> calculations performed by wien2k. We consider a system which is 
> ferromagnetic at its ground state but nonmagnetic at room temperature. 
> We now take an experimental structure (at any temperature) and then 
> geometrically optimize by constraining its magnetism (using 
> runsp_lapw_c.....). Now according to the theory this is a hypothetical 
> structure which represents the nonmagnetic system at 0K. Now is it 
> feasible to approximate the properties of the nonmagnetic system at room 
> temperature by this hypothetical structure?....any response will be 
> greatly appreciated. Thanks in advance.
> 
> with regards,
> 
> Shamik Chakrabarti
> 
>      
> 
> 
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-- 
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Peter Blaha
Inst. Materials Chemistry, TU Vienna
Getreidemarkt 9, A-1060 Vienna, Austria
Tel: +43-1-5880115671
Fax: +43-1-5880115698
email: pblaha at theochem.tuwien.ac.at
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