Crossover from the ballistic to the resonant tunneling transport for an ideal one-dimensional quantum ring with spin-orbit interaction

Quantum interference effects in nanometric devices provide suitable means for controlling spin at mesoscopic scales. As discussed by Foldi [Phys. Rev. B 71, 033309 (2005)], in a quantum ring connected with two external leads, the spin properties of an incoming electron are modified by the spin-orbit interaction (SOI), resulting in a transformation of the qubit state carried by the spin. The ring acts as a one-qubit spintronic quantum gate whose properties can be varied by tuning the Rashba parameter of the SOI, as well as by changing the size of the ring. However continuous transport experiment cannot be utilized as quantum information processing because in spintronics one has to handle a single electron which carries the information in its spin. Thus, starting from the ballistic structure by Foldi , we propose a device which works in the regime of resonant tunneling and is able to handle a single electron. We discuss the crossover between the two different regimes.