Finite shot noise and electron heating at quantized conductance in high-mobility quantum point contacts

Abstract

We report a precise experimental study on the shot noise of a quantum point contact (QPC) fabricated in a GaAs/AlGaAs based high-mobility two-dimensional electron gas (2DEG). The combination of unprecedented cleanliness and very high measurement accuracy has enabled us to discuss the Fano factor to characterize the shot noise with a precision of 1 %. We observed that the shot noise at zero magnetic field exhibits a slight enhancement exceeding the single particle theoretical prediction, and that it gradually decreases as a perpendicular magnetic field is applied. We also confirmed that this additional noise completely vanishes in the quantum Hall regime. These phenomena can be explained by the electron heating effect near the QPC, which is suppressed with increasing magnetic field.

arXiv comment8 pages, 7 figures

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Cited by in corpus (6)

• Shot Noise in Mesoscopic Systems: from Single Particles to Quantum Liquids
• What Can We Learn from Noise? -- Mesoscopic Nonequilibrium Statistical Physics --
• Edge States in Lateral p-n Junctions in Inverted Band HgTe Quantum Wells
• Cryogenic GaAs high-electron-mobility-transistor amplifier for current noise measurements
• Conductance quantization and shot noise of a double-layer quantum point contact
• What can we learn from nonequilibrium response of a strange metal?