[Wien] Magnetism of dilute alloys

[Bin Shao]

Thank you for the reply!

When the RMT is set to be smaller and keep the value of RMT*KMAX the same,
there will be more plane waves in Wien. On the other hand, VASP is package
using a plan wave basis, so I think the results of the two package will be
almost the same when the RMT set to be smaller.

And I did the calculations of the same system FeZn35 with spin and no spin.
The result shows that the total energy of no-spin is -128273.80637250 Ry and
that of spin is -128273.83372717 Ry. The former is smaller, about 0.03 Ry.

On Tue, May 18, 2010 at 2:40 PM, Stefaan Cottenier 
Stefaan.Cottenier at ugent.be wrote:


  I note that the value RMT = 2.25 in my calculation FeZn35 and the value is
 generated automatically according the structure parameters of the system. In
 my opinion, the limitation of the value is zero, in my opinion, the
 calculation equates to VASP in this case.


 (I'm sorry, I don't catch the meaning of your last sentence.)


  My question is whether the value RMT will effect the magnetism property of
 a metal system? How to choose the value of RMT?


 The value of RMT should not affect the type of result you get (i.e. whether
 you find a magnetic or nonmagnetic solution). Small changes in RMT will
 changes to some extent the value of the spin moment reported in :MMIxxx,
 because the latter is the spin moment *within* the muffin tin sphere.
 However, this is only an apparent change. Roughly spoken, you get the same
 charge and spin densities, irrespective of the value of RMT. Only the
 portion of the total spin moment (:MMTOT) which you assign to a particular
 atom (:MMIxxx) is different.

 Stefaan


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-- 
Bin Shao
College of Information Technical Science, Nankai University
94 Weijin Rd. Nankai Dist. Tianjin 300071, China
Email: binshao1118 at gmail.com
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[Wien] Magnetism of dilute alloys

[Stefaan Cottenier]

 When the RMT is set to be smaller and keep the value of RMT*KMAX the 
 same, there will be more plane waves in Wien. On the other hand, VASP is 
 package using a plan wave basis, so I think the results of the two 
 package will be almost the same when the RMT set to be smaller.

Good attempt, but not really true. VASP has plane waves *and* a 
pseudopotential. Therefore, with a reasonable number of plane waves you 
get a good description. If, however, you would set RMT to zero in wien, 
you have an all-electron calculation (no pseudopotential) with a plane 
wave basis. That would require zillions of basis functions -- impossible 
in practice.

 And I did the calculations of the same system FeZn35 with spin and no 
 spin. The result shows that the total energy of no-spin is 
 -128273.80637250 Ry and that of spin is -128273.83372717 Ry. The former 
 is smaller, about 0.03 Ry.

Fine -- this suggests that you should be able to find the magnetic 
solutions with VASP as well.

Stefaan

[Wien] missing case.scf file

[Josh Abeling]

When I run full calculations on the attached Cd2Re2O7.struct file I am not 
getting a case.scf file returned. I get .scf(0-2). Sometimes when I run this 
file I get an error for xdstart, but not always. I have run the WIEN2k 
calculations on many other files and never encountered this behaviour. This 
particular Cd2Re2O7.struct file is part of making input for PHON therefore it 
has one atom displaced from the original file. The other four .struct files 
that correspond to the rest of the displacements run fine and do produce a .scf 
file.

Joshua Abeling
Physics Department
Memorial University of Newfoundland

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