Hello Azar,
First of all, you need a Solid State Physics background to understand these. On Fri, Jun 5, 2015 at 11:29 AM, azar ostovan <[email protected]> wrote: > 1) How I could define suitable band line block for in my .fdf file? > You have to look at the Brillouin zone of your structure. Take a look here: http://en.wikipedia.org/wiki/Brillouin_zone which is based, mainly, in this paper: doi <http://en.wikipedia.org/wiki/Digital_object_identifier>: 10.1016/j.commatsci.2010.05.010 <http://dx.doi.org/10.1016%2Fj.commatsci.2010.05.010> > 2) Band lines depend on what items? > The selection of band lines depends on your will. I mean, the Brillouin zone depends on the symmetry of your structure. Based on that, you have to know the symmetry of your crystal structure, then using the corresponding Brillouin zone, you select a path (band lines, for SIESTA) connecting (in a continuous form) the highly symmetric points. 3) I work on zigzag nanoribon, Do the type of material and the type of > unit cell affect the band lines block? > The type of material do NOT affect the selection of band lines. The type of unit cell DO affect the Brillouin zone, then, the selection of band lines. siesta manual mentioned : > > …. **BandLines (data block): Specifies the lines along which band energies > are calculated (usually > > along high-symmetry directions). An example for an FCC lattice is: > > %block BandLines > > 1 1.000 1.000 1.000 > > 20 0.000 0.000 0.000 \Gamma > > 25 2.000 0.000 0.000 X > > 30 2.000 2.000 2.000 \Gamma > > %endblock BandLines**……. > > 4) How I could find the high-symmetry direction? > Taken a look in the Brillouin zone. The high-symmetry directions are the directions that connect the high-symmetry points. In the pictures (from the Wiki page, above) these high-symmetry points are shown in capital letters, like L, M, A, K, etc. I think that the GDIS (http://gdis.sourceforge.net/) ans XCrySDen ( http://www.xcrysden.org/) can help you to build the band lines (they can not help you to understand
