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

Luke R. Simkins (1) , David G. Rees (1) , Philip H. Glasson (1) , Vladimir Antonov (1) , Eddy Collin (2) , Peter G. Frayne (1) , Philip J. Meeson (1) , Michael J. Lea (1)

1 Department of Physics [Egham]
2 NEEL - UBT - Ultra-basses températures

Charge offsets and two-level fluctuators are common in single-electron transistors (SET) with a typical magnitude |∆Q| < 0.1e. We now present measurements in a 2e-periodic single-Cooper-pair transistor (SCPT) 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 also 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.

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Luke R. Simkins, David G. Rees, Philip H. Glasson, Vladimir Antonov, Eddy Collin, et al.. Thermal excitation of large charge offsets in a single-Cooper-pair transistor. Journal of Applied Physics, 2009, 106 (12), pp.124502. ⟨10.1063/1.3266012⟩. ⟨hal-00917400⟩