SKM 2021 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 3: Poster Session I
HL 3.15: Poster
Monday, September 27, 2021, 10:00–13:00, P
Detection of correlated noise in quantum rings — C. Riha1, S. S. Buchholz1, O. Chiatti1, A. D. Wieck2, D. Reuter3, and •S. F. Fischer1 — 1Novel Materials Group, Humboldt-Universität zu Berlin, 10099 Berlin, Germany — 2Angewandte Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany — 3Optoelektronische Materialien und Bauelemente, Universität Paderborn, 33098 Paderborn, Germany
Cross-correlated noise measurements in equilibrium at a bath temperature of Tbath=4.2 K are performed in etched AlxGa1-xAs/GaAs-based quantum rings [1], which are of interest to the study of mode control and heat flow at the nanoscale and in quantum systems [2].
The measured white noise exceeds the thermal noise expected from the measured electron temperature Te and the electrical resistance R.
This excess noise is neither observed if one arm of a quantum ring is depleted of electrons nor in 1D-constrictions that have a length and width comparable to the quantum rings.
Also, it decreases as Tbath increases and vanishes for Tbath > 12 K.
A model is presented that suggests that the excess noise originates from the correlation of noise sources, mediated by phase-coherent propagation of electrons.
The noise measurements at Tbath=4.2 K allow the estimation of a correlation coefficient from the excess noise.
[1] C. Riha et al., Appl. Phys. Lett. 117, 063102 (2020)
[2] S. S. Buchholz et al., Phys. Rev. B 85, 235301 (2012); C. Kreisbeck et al., Phys. Rev. B 82, 165329 (2010); C. Riha et al., Appl. Phys. Lett. 106, 083102 (2015)