Inspired by recent developments in GaAs-${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As heterostructure fabrication, we propose a simple device based on quantum adiabatic transport that can work as an electron pump. It consists of two gates to which an alternating voltage is applied with a relative phase shift, which breaks the time-reversal symmetry. Its operation relies on the Pauli principle, which leads to a distinction for the electrons transmitted through the device between inelastic emission and absorption processes. Depending on the modulation amplitude, transmission of one electron per photon or of few electrons per cycle can be realized. It is also possible to measure the electron velocity. Since inelastic processes occur in a controlled way, the device can serve to test assumptions about electron reservoirs in the presence of phase breaking.

• Received 21 June 1991

DOI:https://doi.org/10.1103/PhysRevB.44.9110