[Wien] SDW calculation ?

[Lyudmila V. Dobysheva]

Susanta Mohanta wrote
> > My question is regarding the spin structure for a SDW calculation. 

The WIENNCM package that is developed by R Laskowski gives a possibility 
to make an SDW using small unit cell with the help of generalised Bloch 
theorem. Though, it would be interesting to compare the results from both 
methods (large supercell with size equal to the SDW length with common 
WIEN, and the small cell with the SDW of the same commensurate q-vector 
with NCM).

> > the unit cell need to be extended in a particular
> > direction, equivalent or greater than the wave vector
efaan Cottenier wrote
> Generate a default case.inst, which will have initially these occupations:

By the way, from general considerations I am afraid that this method with 
supercell for pure Cr will give bad convergency; namely, no convergency at 
all. One would possibly need to fix the position of the node of the wave, 
somehow. Otherwise, the iteration cycle may jump between equal solutions.

Martin Pieper wrote
>>> If the SDW is not a linear polarized wave but a helical one (I don't 
>>> know for Cr) you will, to my knowledge, also be unable to model it 
>>> exactly using the standard version of Wien2k, which only knows 
>>> colinear spin structures.

WIENNCM makes helical, also.

Best wishes
Lyudmila Dobysheva
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