[Pw_forum] Which coordinates of K point should be used, referencing to reciprocal CONVENTIONAL vectors or reciprocal PRIMITIVE vectors?
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. >> >> >> ___ >> Pw_forum mailing list >> Pw_forum at pwscf.org >> http://www.democritos.it/mailman/listinfo/pw_forum > > > > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum -- Hongsheng Zhao School of Physics and Electrical Information Science, Ningxia University, Yinchuan 750021, China
[Pw_forum] Which coordinates of K point should be used, referencing to reciprocal CONVENTIONAL vectors or reciprocal PRIMITIVE vectors?
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 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. > > > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20110630/48c035c3/attachment.htm
[Pw_forum] Which coordinates of K point should be used, referencing to reciprocal CONVENTIONAL vectors or reciprocal PRIMITIVE vectors?
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. -- Hongsheng Zhao School of Physics and Electrical Information Science, Ningxia University, Yinchuan 750021, China -- next part -- A non-text attachment was scrubbed... Name: BZ.png Type: image/png Size: 116984 bytes Desc: not available Url : http://www.democritos.it/pipermail/pw_forum/attachments/20110629/979a2a6f/attachment-0001.png
[Pw_forum] Which coordinates of K point should be used, referencing to reciprocal CONVENTIONAL vectors or reciprocal PRIMITIVE vectors?
On 06/29/2011 11:24 AM, jia chen wrote: > Hi Hongsheng, > > You can find definitions of lattice vectors in INPUT_PW.txt and > calculate reciprocal vectors according to definition of reciprocal > vector. The name sometimes doesn't matter. Good, thanks a lot. I've got it. Regards. -- Hongsheng Zhao School of Physics and Electrical Information Science, Ningxia University, Yinchuan 750021, China
[Pw_forum] Which coordinates of K point should be used, referencing to reciprocal CONVENTIONAL vectors or reciprocal PRIMITIVE vectors?
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) P. --- Paolo Giannozzi, Dept of Chemistry&Physics&Environment, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
[Pw_forum] Which coordinates of K point should be used, referencing to reciprocal CONVENTIONAL vectors or reciprocal PRIMITIVE vectors?
Hi all, For a set of lattice vectors used for our supercell, the corresponding reciprocal vectors may have two different forms: reciprocal CONVENTIONAL vectors and reciprocal PRIMITIVE vectors. In this case, the coordinates of K point used in the calculations should reference to reciprocal CONVENTIONAL vectors or reciprocal PRIMITIVE vectors? Regards. -- Hongsheng Zhao School of Physics and Electrical Information Science, Ningxia University, Yinchuan 750021, China
[Pw_forum] Which coordinates of K point should be used, referencing to reciprocal CONVENTIONAL vectors or reciprocal PRIMITIVE vectors?
Hi Hongsheng, You can find definitions of lattice vectors in INPUT_PW.txt and calculate reciprocal vectors according to definition of reciprocal vector. The name sometimes doesn't matter. Best Wishes jia On Tue, Jun 28, 2011 at 8:16 PM, Hongsheng Zhao wrote: > Hi all, > > For a set of lattice vectors used for our supercell, the corresponding > reciprocal ?vectors may have two different forms: ?reciprocal > CONVENTIONAL vectors and reciprocal PRIMITIVE vectors. ?In this case, > the ? coordinates of K point used in the calculations should reference > to reciprocal CONVENTIONAL vectors or ?reciprocal PRIMITIVE vectors? > > Regards. > -- > Hongsheng Zhao > School of Physics and Electrical Information Science, > Ningxia University, Yinchuan 750021, China > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- Jia Chen
