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

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...

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Bibliographic Details
Published in:Physical review. B 2016-05, Vol.93 (19), Article 195411
Main Authors: Muro, Tatsuya, Nishihara, Yoshitaka, Norimoto, Shota, Ferrier, Meydi, Arakawa, Tomonori, Kobayashi, Kensuke, Ihn, Thomas, Rössler, Clemens, Ensslin, Klaus, Reichl, Christian, Wegscheider, Werner
Format: Article
Language:English
Subjects:
Condensed matter
Conductance
Heating
Magnetic fields
Mathematical analysis
Point contact
Shot noise
Two dimensional
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Summary: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 0.01. 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.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.93.195411