[Wien] Hi

[Mathrubutham Rajagopalan]

Dear Dr Blaha,
Greetings from Rajagopalan Anna University Chennai
I am doing the Band structure calculation for Co2FeSi
The space group is 225 The lattice parameter is taken from the x-ray work
I like to see the half metallicity in the compound
I did LDA, GGA and LSDA+U
By doing doing LSDA+U I am able to see half metallicity in the compound and
I am able to get the gap also
Next I like to calculate the elastic properties
Here I am facing a problem
I am getting a negative value for C44 and C11 -- C!2 is also negative
This means that the system is not stable in this structure
I repeated the calculation number of times and I am getting the same result
I calculated the elastic properties for number of A3B compounds and checked
with the reported results I get a good agreement
I donot know why for this compound namely Co2FeSi I am getting such a result
Will you kindly tell me the possible reason
As per x-ray results the space group is 225 for Co2FeSi and it is stable
Regards and greetings
Rajagopalan

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Dr M.Rajagopalan
Emeritus Scientist (CSIR)
Crystal Growth Center                20 6th Main Road
Anna University                          Chromepet
Chennai 600 025                         Chennai 600 044
Phone #  22213023 (R)
         22359208 (O)
Mobile  9445125709

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