Conductance Cusp of a Driven Mesoscopic Ring

Abstract

A new type of photon-assisted tunneling (PAT) which will occur in a Mach-Zender electron interferometer with a δ-function time-varying potential is analytically predicted. In contrast to conventional PAT in Fabry-Perot electron interferometers, quite acute and cusp-like PAT signals appear in the conductance of the system. The width of the cusp is proportional to u₁²/ω, where u₁ and ω are the strength and the frequency of the time-varying potential. Numerical calculations using a transfer matrix technique show that this type of PAT will be observed in actual experiments where the time-varying potential has a broader spatial profile and the temperature is finite.