Coulomb-Regulated Conductance Oscillations in a Disordered Quantum Wire
Disordered quantum wires have been defined by means of a splitgate lateral depletion technique in the two-dimensional electron gas in GaAs-AlGaAs heterostructures, the disorder being due to the incorporation of a layer of beryllium acceptors in the 2DEG. In contrast to the usual aperiodic conductance fluctuations due to quantum interference, periodic conductance oscillations are observed experimentally as a function of gate voltage (or density). No oscillations are seen in the magnetoconductance, although a strong magnetic field dramatically enhances the amplitude of the oscillations periodic in the gate voltage. The fundamentally different roles of gate voltage and magnetic field are elucidated by a theoretical study of a quantum dot separated by tunneling barriers from the leads. A formula for the periodicity of the conductance oscillations is derived which describes the regulation by the Coulomb interaction of resonant tunneling through zero-dimensional states, and which explains the suppression of the magnetoconductance oscillations observed experimentally.
KeywordsCoherence GaAs Kelly Beryllium Verse
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