Quantized current in a quantum-dot turnstile using oscillating tunnel barriers

Abstract

We have observed a quantized current in a lateral quantum dot, defined by metal gates in the two-dimensional electron gas (2DEG) of a GaAs/AlGaAs heterostructure. By modulating the tunnel barriers in the 2DEG with two phase-shifted rf signals, and employing the Coulomb blockade of electron tunneling, we produced quantized current plateaus in the current-voltage characteristics at integer multiples of ef, where f is the rf frequency. This demonstrates that an integer number of electrons pass through the quantum dot each rf cycle.