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["zzzhong" <zzzhong@red.semi.ac.cn>]

Dear Javad hashemifar,hello!

        I have calculate MnAs half-metal like your CrAs. But I use VASP. I 
think you want to calucluate the exchange parameter, such as the N0_alpha and 
N0_beta. Because the DOS calucation maybe use the extend function, such as 
Gauss. Maybe you can draw band struture near the Gamma point using abinit and 
Wien2k. You can compare the VB spilting and CB spliting between up and down. 
Because it is different between the Wien2k and abinit calculation method, 
Wien2k It is based on the full-potential augmented plane-wave, Abinit use the 
PP. The results between those is a bit different. For I have not Wien2k, I 
don't compare the results between VAPS and Wien2k and know how big are the 
diffences.  

======= 2006-12-08 15:54:45 您在来信中写道：=======

>Dear Matthieu
>
>I benefit from your kind explanations especially about core correction
>techniques.
>But still I am not sure about my results. I am not worry about the
>wiggles of DOS but the main problem is the nontrivial difference
>between up and down splittings (exchange splitting) of Abinit and
>Wien2k. I plotted the DOSs again to make this problem more visible
>(please see attachment). As it is clear, the splitting of the main up
>and down peaks (~0.1 Ryd below the Fermi level) in Wien2k (~0.03 Ryd)
>is considerably larger than Abinit (~0.01).
>Is there any way to remove this difference or I should consider it as
>a trivial difference and simply neglect it.
>
>Thanks in advance.
>Javad Hashemifar
>
>
>
>On 12/7/06, Matthieu Verstraete <mjv500@york.ac.uk> wrote:
>>
>> On the contrary! This is really a very good result for the
>> pseudopotentials. The core corrections is obviously necessary in an
>> element with high lying core states, but the results are as close as you
>> can expect them in the pseudopotential approximation.
>>
>> If you are concerned about the wiggles in the abinit DOS, they come from
>> the kpoint sampling and the way the DOS is calculated. Use prtdos 2 to get
>> a smoother results with the tetrahedron method (which is certainly what is
>> used in wien).
>>
>> Your last phrases were a bit worrying, it sounded like you were changing
>> convergence parameters to get the DOS closer to the wien one. You must not
>> do this! You should converge the kpoints, ecut, etc... until the results
>> do not change anymore. They are not free parameters.
>>
>> The psp core radii and NLCC parameters are a bit trickier, but normally
>> fitting the psp for the free atom should be enough to give you a nice
>> transferable potential (well, not always strictly true). As you can see,
>> changing the NLCC parameter does change the DOS, but mainly in the
>> unoccupied states. There is a general recipe for setting the rnlc to the
>> radius at which the valence density becomes larger than the core density,
>> but this is a bit arbitrary. In many cases, people do what you have done
>> here, and use the rnlc which best reproduces an all electron calculation.
>>
>> Matthieu
>>
>> --
>> ================================================================
>> Dr. Matthieu Verstraete                 mailto:mjv500@york.ac.uk
>> Dept. of Physics, University of York,     tel: +44 1904 43 22 08
>> Heslington, YO10 5DD York, United Kingdom fax: +44 1904 43 22 14
>>
>
>
>-- 
>======================================
>Seyed Javad  Hashemifar,    Ph.D.
>[current:]
>Tel:+49-203-3794743        Fax:+49-203-3794742
>Fachbereich Physik (AG Kratzer), Universitat Duisburg-Essen
>47048 Dusiburg, Germany
>[permanent:]
>Tel:  +98-311-3912375       Fax: +98-311-3912376
>Physics Department, Isfahan University of Technology
>84156 Isfahan, Iran
>---------------------------------------------------------------------------
>

= = = = = = = = = = = = = = = = = = = =
   Best regards
                                 
　 zzzhong
   State Key Laboratory for Superlattices and Microstructures
　 Institute of Semiconductors
   Chinese Academy of Sciences
   P. O. Box 912, Beijing 100083
　 Eamil: zzzhong@red.semi.ac.cn
　 2006-12-08