El 27-12-2018 14:37, Josue Itsman Clavijo Penagos escribió: > Dear Maria, have a nice research day. Before trying an answer to your > questions, a kind reminder of some posting guidelines: > > Please always include you affiliation/granting institute. > > Present yourself politely, and insofar do not link to other forum/posts > outside QE-users mailing lists; it's not neither nice nor common practice to > do that. > > Now, regarding your questioning, high-simmetry points in reciprocal space are > used becaused they best describe the simplest (and the shortest, as far as I > remember) paths a travelling periodic wave (bloch solutions) can take to move > out through the crystal; the precise location of those points depends on the > space group the crystal structure shows. > > So if one study the Band structure at those high-simmetry points, bassically > all the E-k relationship are determined for electrons in the material under > study. > > On the computing side, bands.x produces a x-coordinate values sequence to > map the k points path in the same order you have specified previously; so, if > your set the following path for the Si primitive cell (as recommended in > HINUMA _ET AL_, _Band structure diagram paths based on crystallography_, > HTTPS://ARXIV.ORG/ABS/1602.06402, there are two different recommended k-paths > for Si, not connected by shortest distances between the U and K points) > > K_POINTS crystal_b > > 0.0000000000 0.0000000000 0.0000000000 10 > 0.5000000000 0.0000000000 0.5000000000 10 > 0.6250000000 0.2500000000 0.6250000000 1 > 0.3750000000 0.3750000000 0.7500000000 10 > 0.0000000000 0.0000000000 0.0000000000 10 > 0.5000000000 0.5000000000 0.5000000000 10 > 0.5000000000 0.2500000000 0.7500000000 10 > 0.5000000000 0.0000000000 0.5000000000 1 > > bands.x will generate > > 10 intermediate k-points in between Gamma->X (Beginning of first path) > 10 intermediate k-points in between X->U > 1 k-point at U (End of first path) (When you plot, draw a thick vertical line > at this point to make clear this is the end of the path and that there is no > connection with the next point - K - also). > 10 intermediate k-points in between K-->Gamma (Beginning of second path) > 10 intermediate k-points in between Gamma->L > 10 intermediate k-points in between L->W > 10 intermediate k-points in between W->X > 1 k-point at X (end of second path) > > That is, 62 k-points for the recommended paths Γ--X--U|K--Γ--L--W--X. > > By the way, the plot you show in physics.stackexchange.com [1] uses a custom > selected k-path. One can choose the k-path that best fits/likes oneself, but > the recommended one is just enough. Citing the hinuma _et al_ paper, the > recommend k-path is the one that "_cover all special wavevector (k -vector) > points and lines necessarily and sufficiently_". > > So you can see/copy/build the suggested k-points path for your different > structures by uploading your *.cif/*.pw.in [2] files in > https://www.materialscloud.org/work/tools/seekpath > > Hope all of this helps. > > Best regards and happy holydays! > > _PROFESSOR JOSUÉ CLAVIJO, PH.D._ > > CHRISTIAN, BORN AGAIN > > _Assistant Professor_ > Universidad Nacional de Colombia > Bogotá DC > Facultad de Ciencias > Departamento de Química > 571-3165000 Ext. 14445 > > [email protected] > [email protected] > _______________________________________________ > users mailing list > [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users
Thanks Mr Clavijo. This solved the question I had. I'm sorry I didn't present myself properly, I honestly wasn't aware of the guidelines. And the reason I put the link instead of writing my question here was due to format. By using the institutional mail I cannot put images in certain order, just attach them. And also the code chunks look better in that particular web forum. But in any case I won't do it again. Have a nice day and thanks for your help. Kind regards, María. Links: ------ [1] http://physics.stackexchange.com [2] http://pw.in
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