Hi all,
I have a question regarding some transmission+DOS calculations I have done on a couple of different structures.
First, I am working with a Cu/Si interface. Deep inside the Si, there should naturally be a band gap. As far as my intuition goes, that should create a transmission gap in the whole structure because states in that energy range in the Cu cannot propagate once they reach the Si, correct?
The transmission gap is significantly smaller than the bulk Si band gap, but I guess that it is because of the systematic error with DFT calculations and band gaps.
Nevertheless I see a finite DOS for all energies. I am guessing that this is because of induced states from the Cu (metal induced gap states) that reach several atomic layers into the Si part. So the DOS is calculated by adding up all states in the whole structure for each energy, but because there is bulk Si in the structure, some states will not propagate because of the band gap. Any thoughts?
Now a more serious problem. I also calculate transmission+DOS for Bulk Si along different directions.
I do see a band gap, but no transmission gap ! How can that be possible? I can see how some states would not conduct, but not how I can have transmission without states. Especially for bulk Si where there should definitely be a band gap and transmission gap?
Thanks for any thoughts!
