Shot noise suppression in InGaAs/InGaAsP quantum channels

TL;DR

This paper reports measurements of shot noise in an InGaAs/InGaAsP quantum point contact, providing experimental evidence of quantized conductance channels and analyzing deviations caused by electron heating effects.

Contribution

It presents the first experimental observation of shot noise suppression in InGaAs/InGaAsP QPCs, confirming coherent quantized channel formation.

Findings

Reduced shot noise at conductance plateaus N(2e^2/h)

Deviation from theory explained by electron heating

Evidence of coherent quantized channels

Abstract

We have measured the shot noise in a quantum point contact (QPC) fabricated by using InGaAs/InGaAsP heterostructure, whose conductance can be electrically tuned by the gate voltages. The reduced shot noise is observed when the QPC conductance equals to N(2e^2/h) (N=4, 5, and 6), which is the direct experimental evidence of the coherent quantized channel formation in the QPC. The deviation of the observed Fano factor from the theory is explained by the electron heating effect generated at the QPC.