Adiabatic quantum pumping in an Aharonov-Bohm loop and in a Si-like nanowire: interference in real space and in k-space

We study interference effects in the current generated by adiabatic quantum pumping in two extended chain models. The first model contains an Aharonov-Bohm loop within a tight-binding chain of sites. It exhibits interference between the two arms of the loop. We investigate the effect of magnetic field reversal on the pumped current. Our second model is a tight-binding chain of sites with next-nearest-neighbor hopping terms. The resulting Si-like indirect band structure can have 4 degenerate Fermi wave vectors $\pm k_{1F}$ and $\pm k_{2F}$ rather than the usual 2 Fermi wave vectors $\pm k_{F}$. It exhibits signatures of interference between these degenerate conduction band states.