[Pw_forum] band-structure calculations in slab-vacuum geometry: how to find the "surface k-path"?

[Christoph Wolf(신소재공학과)]

Dear all!

I have come across an impasse  and I am hoping for some stimulating input…

I work on CsPbBr3 (cubic unit cell, a=5.6 A). I construct a  vacuum (5L)-slab (7L)-vacuum (5L) (L=layer numbers in multiple of the lattice constant in z-direction) symmetric slab (exposing the 100 CsBr terminated surface) and calculate the SCF/NSCF after a relax run. During relaxing the surface layer moves slightly “into the vacuum”, by ~5% (d12) and the next layer moves  slightly inwards by ~2% (d23). Pp.x gives nice electron density surfaces and potentials (plot_num=0,11);

Now I wanted to plot the band-structure to investigate the influence of slab geometry on the band-structure but I am (shameful!) not sure how to define the k-path in order to get a “surface” band-structure. Frankly speaking, I am not entirely sure that would be even physically meaningful, but I have seen similar calculations for other slab geometries  (e.g. https://arxiv.org/pdf/1609.09262.pdf).

I attached the input file to the nscf calculation (i.e. after the relax run) to illustrate the geometry, any help is greatly appreciated!

Yours,
Chris

Postech University
Materials Science and Engineering
Pohang, ROK


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