Time-dependent simulations of electron transport through a quantum ring: Effect of the Lorentz force

Abstract

The time-dependent Schrödinger equation for an electron passing through a semiconductor quantum ring of nonzero width is solved in the presence of a perpendicular homogeneous magnetic field. We study the effects of the Lorentz force on the Aharonov-Bohm oscillations. Within the range of incident momentum for which the ring is transparent at zero magnetic field, the Lorentz force leads to a decrease of the oscillation amplitude, due to the asymmetry in the electron injection in the two arms of the ring. For structures in which the fast electrons are predominantly backscattered, the Lorentz force assists in the transport, producing an initial increase of the corresponding oscillation amplitude. Furthermore, we discuss the effect of elastic scattering on a potential cavity within one of the arms of the ring. For the cavity tuned to shift maximally the phase of the maximum of the wave packet we observe a π shift of the Aharonov-Bohm oscillations. For other cavity depths oscillations with a period of half of the flux quantum are observed. © 2005 The American Physical Society.