Shot noise and the Luttinger liquid-like properties of the FQHE

Abstract

We present shot noise measurements in the Fractional Quantum Hall regime at ν= 1 3 . The two fractional edge channels which carry the current at the two opposite boundaries of a quantum Hall sample are weakly coupled by an artificial impurity, namely a Quantum Point Contact. This coupling gives rise to a current between the two edge channels and the random transfer of the charges gives rise to fluctuations of the current. For a weak coupling and for large voltages, recent experiments have established that the current noise power S I is proportional to the backscattered current I B and to the fractional charge e/3. For low voltages at low temperature, the chiral Luttinger liquid models suggest a renormalization of the coupling strength leading to strong backscattering even when the bare coupling is weak. These models predict a noise power proportional to the transmitted current I and to the electronic charge e. The new noise measurements presented here confirm the shot noise predictions at moderately low temperatures. However, at very low temperature, measurements show a surprising enhancement of the shot noise which is nearly doubled.