Journal of Applied Physics

Thermal excitation of large charge offsets in a single-Cooper-pair transistor

L. R. Simkins, D. G. Rees, P. Glasson, Vladimir N Antonov, Eddy Collin, P.G. Frayne, P. J. Meeson, M. J. Lea

Published Dec 15, 2009• 5 citations

Abstract

Charge offsets and two-level fluctuators are common in single-electron transistors with a typical magnitude of |ΔQ|<0.1e. We present measurements in a 2e-periodic single-Cooper-pair transistor which exhibited hysteretic charge offsets close to 1e. The real-time capture and escape of individual electrons in metastable trapped states was measured at very low temperatures. This enabled the dynamics of the transitions to be investigated in detail, demonstrating thermal excitation to a hysteretic tunneling transition. We show that, allowing for the hysteresis, the metastable states are in thermal equilibrium with each other. The observed temperature dependence and hysteresis can be explained by the coupling of a two-level fluctuator to a quasiparticle trap.

DOI: 10.1063/1.3266012

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