Non-Gaussian distribution of nearest-neighbour Coulomb peak spacings in metallic single-electron transistors

¹ Solid State Physics Laboratory, ETH Zürich - CH-8093 Zürich, Switzerland
² Swiss Federal Office of Metrology OFMET - CH-3003 Bern-Wabern, Switzerland
³ Physikalisch-Technische Bundesanstalt PTB - D-38116 Braunschweig, Germany

Received: 7 September 1999
Accepted: 18 November 1999

Abstract

The distribution of nearest-neighbour spacings of Coulomb blockade oscillation peaks in normal conducting aluminum single-electron transistors is found to be non-Gaussian. A pronounced tail to reduced spacings is observed, which we attribute to impurity-specific parametric charge rearrangements close to the transistor. Our observation may explain the absence of a Wigner-Dyson distribution in the experimental nearest-neighbour spacing distributions in semiconductor quantum dots.