Conductance Anomaly and Fano Factor Reduction in Quantum Point Contacts

Abstract

We report an experimental study on the shot noise as well as the dc transport properties of a quantum point contact (QPC) whose conductance anomaly can be tuned electrostatically by the gate electrodes. By controlling the single QPC so that it has no anomaly or an anomaly at $0.5G_0$, $0.8G_0$ or $0.9G_0$ ($G_0=2e^2/h$), we prove that the anomaly always accompanies the Fano factor reduction due to the asymmetric transmission of the two spin-dependent channels for the conductance lower than $G_0$. For the QPC tuned to have the anomaly at $0.5G_0$ the channel asymmetry is found to be as large as 67% with the spin gap energy gradually evolving as the conductance increases.

RevTex, 4 pages, 3 figures

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Cited by in corpus (13)

• What lurks below the last plateau: Experimental studies of the 0.7 x 2e^2/h conductance anomaly in one-dimensional systems
• Non-equilibrium Fluctuation Relations in a Quantum Coherent Conductor
• Evolution of the Kondo Effect in a Quantum Dot Probed by the Shot Noise
• Shot Noise in Mesoscopic Systems: from Single Particles to Quantum Liquids
• Fluctuation Theorem and Microreversibility in a Quantum Coherent Conductor
• On the relation between the 0.7-anomaly and the Kondo effect: Geometric Crossover between a Quantum Point Contact and a Kondo Quantum Dot
• Shot Noise Induced by Electron-nuclear Spin-flip Scattering in a Nonequilibrium Quantum Wire
• What Can We Learn from Noise? -- Mesoscopic Nonequilibrium Statistical Physics --
• Finite shot noise and electron heating at quantized conductance in high-mobility quantum point contacts
• Temperature dependence of the visibility in an electronic Mach-Zehnder interferometer
• Conductance quantization and shot noise of a double-layer quantum point contact
• Fano-Kondo and the Kondo-box regimes crossover in a quantum dot coupled to a quantum box
• Noise of a superconducting magnetic flux sensor based on a proximity Josephson junction