Dynamics of a two-level fluctuator in a single-electron transistor

We report on the detailed behavior of a two-level fluctuator (TLF) in an Al-Al ₂ 0 ₃ -Al single-electron transistor. The TLF was measured from 85 mK to 3 K and induced a charge shift of Δ Q~= e/10. Below about 0.5 K, the lifetimes τ _l and τ _s of the two states become independent of the temperature. Moreover, they are periodic in the gate voltage and τ _l varies non-monotonically with the bias voltage. We describe our exploration of possible mechanisms driving the TLF, in particular inelastic scattering between the charged TLF and transport electrons.