Influence of Fringe Fields on Eleetrostatic Aharonov-Bohm Effects in Mesoscopie Ring

概要

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A new method is invented to treat electron transport in the Aharonov-Bohm (AB)-type ring geometry where transport in each branch of the ring can be treated separately in terms of transfer matrix theory. The influence of fringe field due to the potential edge on the AB effect in a mesoscopic ring is thereby formulated. In the case of potential with an abrupt step, it is found by numerical calculations that the standard treatment of AB effects is approximately permissible at a low enough electrostatic potential of practical interest. The phase of quantum oscillation, however, shifts towards low electrostatic potential, and the amplitudes slowly decay as a function of electrostatic potential as it becomes high. In the case of realistic potential with gradual steps, the transfer matrix can be written in an ordered product of infinitesimal matrices causing AB phase shift and electric-field-dependent amplitude modulation. It is shown that the validity of the usual AB treatment can be assessed in terms of the concept of adiabatic condition.
社団法人応用物理学会の論文
1993-10-15