Single-electron transport in a one-dimensional channel by high-frequency surface acoustic waves

Abstract

We report a detailed experimental study of the quantized acoustoelectric current induced by a surface acoustic wave in a one-dimensional channel defined in a ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}\ensuremath{-}\mathrm{A}\mathrm{l}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$ heterostructure by a split gate. The current measured as a function of the gate voltage demonstrates quantized plateaus in units of $I=ef$ where $e$ is the electron charge and $f$ is the surface acoustic wave frequency, the effect first observed by Shilton et al. The quantization is due to trapping of electrons in the moving potential wells induced by the surface acoustic wave, with the number of electrons in each well controlled by electron-electron repulsion. The experimental results demonstrate that acoustic charge transport in a one-dimensional channel may be a viable means of producing a standard of electrical current.