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Quantized acoustoelectric current in a finite-length ballistic quantum channel: The noise spectrum

Y. M. Galperin, O. Entin-Wohlman, Y. Levinson

cond-mat.mes-hallarXiv:cond-mat/0011363

Abstract

Fluctuations in the acoustoelectric current, induced by a surface acoustic wave propagating along a ballistic quantum channel, are considered. We focus on the large wave-amplitude case, in which it has been experimentally found that the current is quantized, and analyze the noise spectrum. A phenomenological description of the process, in terms of a random pulse sequence, is proposed. The important ingredients of this description are the probabilities, pn, for a surface acoustic wave well to capture n electrons. It is found that from the noise characteristics one can obtain these probabilities, and also estimate the typical length scales of the regions in which the electrons are trapped.

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