Importance of backscattering effects in ballistic quantum transport in mesoscopic ring structures

We have found that in the ballistic electron transport in a ring structure, the junction-backscattering contribution is critical for all the major features of the Aharonov-Bohm-type interference patterns. In particular, by considering the backscattering effect, we present new and clear interpretation about the physical origin of the secondary minima in the electrostatic Aharonov-Bohm effect and that of the h/2e oscillations when both the electric and magnetic potentials are present. We have devised a convenient scheme of expanding the conductance by the junction backscattering amplitude, which enables us to determine most important electron paths among infinitely many paths and to gain insight about their contributions to the interference patterns. Based on the scheme, we have identified various interesting interference phenomena in the ballistic ring structure and found that the backscattering effect plays a critical role in all of them.