Thanks for the reply. Taking the limit of what you've said, Andrei - if you want a really slow dispersion in the k_z direction, it would presumably be best to work with a thin (i.e zero thickness) slab. This would mean the dispersion in the k_z direction should be infinitely slow - right?
This is in fact the sort of thing I've been doing, using just the surface layer to 'eyeball' the 'surface' bands, then comparing this with the dispersions taken from the slab calculation. The problem is the bands tend to distort and shift in energy as the bulk is re-attached, making the process certainly tricky, and possibly unreliable. It also doesnt pick up surface states induced by the reattachment of the bulk. Is there any sense to taking a series of (k_x,k_y) dispersions at different k_z and working with them? Again, in the limit of what you've suggested, the sub-surface states should just fill common regions but I dont know if the surface states could be particularly enhanced in this way. On Tue, Apr 20, 2010 at 5:50 PM, <[email protected]> wrote: >> I'm sure this is well known to those who know, but how can I extract >> the surface band structure from a slab calculation? >> >> More specifically, I dealing with 10-12 layer slabs, seperated by vacuum. >> >> What do I put into the block "BandLines" to get the surface BZ, i.e >> the projection of the bulk BZ in the direction perpendicular to the >> surface? If I have the surface in the (x,y) direction, for example, >> how would I then set the z value of the vectors in "BandLines"? >> >> I'm guessing it's the same as the 1st BZ edge in that (z) direction, >> but I'm guessing... >> >> With thanks >> >> Ian Shuttleworth > > > Dear Ian, > > as you are interested in the dispersion over (k_x,k_y) plane only, > and the k_z dispersion is (hopefully) negligible, you can take > k_z=0 (or, any other value :-) everywhere > when scanning the 2-dim. Brilluin zone. In practical terms, you'll have > many bands which will project onto the same regions in the 2-dim BZ, > filling it densely (in the limit of infinitely many layers) while > leaving other regions open. > > Figs.6,7 of PRB65, 184412 show an example of what you may expect. > > Best regards > > Andrei Postnikov > >
