R. V. Jensen | PubMed Health

PubMed1993

Order and chaos in semiconductor microstructures.

The semiclassical theory of ballistic electron transport in semiconductor microstructures provides a description of the quantum conductance fluctuations in terms of the classical distributions for the lengths and directed areas of the scattering trajectories. Because the classical dynamics differs for integrable (circular) and chaotic (stadium) scattering domains, experimental measurements of the conductance of these microstructures provide a unique probe of the quantum properties of classically regular and chaotic systems. To advance these theoretical and experimental studies we compare geometrical formulas for the classical distributions of lengths and areas with numerical simulations for microstructures examined in recent experiments, we assess the effects of lead size and placement, and we provide a critical analysis of the role of scattering "noise" on the classical and semiclassical predictions. Finally, we present a detailed comparison of the semiclassical theory with recent experimental measurements of the conductance fluctuations in circular- and stadium-shaped microstructures.

Journal Article↗

PubMed1991

Chaotic scattering, unstable periodic orbits, and fluctuations in quantum transport.

The field of quantum chaos has recently focused attention on the quantum description of chaotic scattering processes. The new physical intuition, analytical methods, and numerical tools developed in the study of the quantum behavior of classically chaotic bound systems, like quantum billiards or atoms in strong fields, has led to exciting new predictions for the scattering of electromagnetic waves in curved waveguides, electrons in mesoscopic wires, and atoms off molecules. After a brief review of recent progress in the field of quantum chaos, this paper focuses on specific results relating to ballistic electron transport in small, mesoscopic devices. Several specific geometries are suggested for experimental studies of this "game" of quantum pinball with explicit predictions for the fluctuations in the electrical conductivity as functions of the electron Fermi energy and of an applied magnetic field.

Journal Article↗