Quantum transport in periodically modulated electron waveguides*

Recent experiments on nanowires written on LAO/STO interfaces have shown their conductive properties are highly controllable and display a range of interesting physics. For example, it has been observed that these display quantized conductance. New experiments apply a periodic potential in the nanowire, displaying a fracturing of the lowest transconductance peak and a 2e^2/h first peak that is not split by magnetic fields up to 16T. We present theoretical descriptions of how these features occur. We first study how the single-particle features change under a periodic potential modulation, and show that this can fracture the transconductance peak. Additionally, we consider that the modulations engineer a spin-orbit coupling, and we study its effect on the single particle regime. Finally, to describe the conductance plateau of 2e^2/h, we introduce electron-electron interactions, and show that the engineered spin-orbit coupling enhances the interactions and leads to a pairing of the lowest energy spin-subbands.