|Dr. Matthew Benesh|
University of Cambridge
Acoustic Transport in Low-Dimensional Electron Systems
Advances in semiconductor material growth have provided the means to investigate electron systems confined to fewer than three dimensions. Certain III-V materials, such as GaAs and AlGaAs, are ideal for creating a perfectly two-dimensional electron gas (2DEG). Through the suitable application of surface voltages, a 2DEG may be further constrained to define one-dimensional quantum wires and zero-dimensional quantum dots, as well as intricate combinations of the two. These systems have proven indispensable to the study of charge transport dynamics at the quantum level.
A novel approach to induce charge transport relies on the piezoelectric qualities of GaAs. By applying a surface acoustic wave (SAW) to a GaAs/AlGaAs system, a traveling electrostatic wave is generated which is able to interact with an embedded 2DEG. When combined with surface voltages, a SAW is capable of capturing electrons and transporting them at the acoustic velocity of 2800m/s. This technique has a wide range of applications, from single-photon sources to quantum computation. In this talk I will introduce the basic concepts and motivation behind acoustoelectric transport, as well as key developments in the field. This will be followed by a discussion of recent investigations of the dynamics of SAW-transport, including loss mechanisms and the quantum-mechanical characteristics of single-electron transport.
*now at Maxim Integrated, Inc.