Hi,
`lead.cell_hamiltonian()` gives 32000. The thickness of my slab is 50. Is this something not possible to calculate?
Ok, now it certainly makes sense that the memory blows up; the kwant paper[1] indicates that the memory requirement for solving this sort of size should be ~ 100GB. Anton reminded me of a workaround written by Christoph for dealing with periodic systems. You can find the code over here[2] (if you don't want to download it using git you can get the raw python module here[3]). You should be able to use this instead of replicating your unit cell in the y direction, which should drastically reduce your memory/runtime requirements. Thanks, Joe [1]: http://downloads.kwant-project.org/doc/kwant-paper.pdf [2]: https://gitlab.kwant-project.org/cwg/wraparound [3]: https://gitlab.kwant-project.org/cwg/wraparound/raw/master/wraparound.py