[Pw_forum] Which coordinates of K point should be used, referencing to reciprocal CONVENTIONAL vectors or reciprocal PRIMITIVE vectors?

[Hongsheng Zhao]

On 06/30/2011 03:48 PM, Stefano de Gironcoli wrote:
> for certain bravais lattice (notably the cubic ones) XCrysDen sometime
> recognizes the conventional unit cell (the cube).
> pw always works in the primitive unit cell, the one defined by the
> fundamental lattice vectors.
>
> Beware that this depends on your input.
> if you define an FCC crystal using a SC Bravais lattice and putting 4
> atoms in the unit cell the BZ displayed is going to be the one for SC

Thanks a lot.  So the correct way is give the correct  primitive unit 
cell vectors in the input file.  Otherwise, it may cause a waste of time 
and cpu.

Regards.
>
> stefano
>
> On 06/29/2011 02:30 PM, Hongsheng Zhao wrote:
>> On 06/29/2011 02:29 PM, Paolo Giannozzi wrote:
>>> On Jun 29, 2011, at 2:16 , Hongsheng Zhao wrote:
>>>
>>>> > For a set of lattice vectors used for our supercell, the
>>>> corresponding
>>>> > reciprocal vectors may have two different forms:
>>> no, the three vectors that generate the reciprocal lattice are uniquely
>>> determined by the three lattice vectors that generate the lattice:
>>> b_i = 2pi (a_j x a_k)/(a_1 . a_2 x a_3)
>>
>> From the k path selection function of xcrysden, for specific lattice,
>> you can see two options in the band path selection panel: Primitive
>> Brillouin Zone and Conventional Brillouin Zone. If only one set of
>> unique reciprocal vectors was generated for three real lattice
>> vectors, what is the difference between Primitive Brillouin Zone and
>> Conventional Brillouin Zone?
>>
>> Attached please find the the BZ for Si from within xcrysden, could you
>> please give me some hints?
>>
>> Regards.
>>
>>
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>
>
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-- 
Hongsheng Zhao <zhaohscas at yahoo.com.cn>
School of Physics and Electrical Information Science,
Ningxia University, Yinchuan 750021, China