Conductance fluctuations and quantum chaotic scattering in semiconductor microstructures

Abstract

We review recent experiments on aperiodic conductance fluctuations in ballistic GaAs/AlGaAs microstructures in the shape of a stadium billiard and a circle with point‐contact leads, measured at millikelvin temperatures. Much of the observed behavior can be analyzed within a semiclassical approach to quantum chaotic scattering. After a brief review of the Landauer–Büttiker formulation of coherent transport, a variety of novel experimental phenomena and comparisons to semiclassical theory are presented. In particular, we discuss quantum‐enhanced backscattering, the power spectrum of conductance fluctuations, crossover to the high‐magnetic‐field and tunneling regimes, and an application allowing the rate of phase‐randomizing scattering to be measured in chaotic ballistic microstructures.