n coherent conducting multilayers with junction transparencies D comparable to unity, quantum fluc- tuations, which follow from the probabilistic nature of the backscattering restricted by the Pauli prin- ciple, are reduced in comparison to the standard Schottky result. Voltage dependence of the low- temperature shot noise is calculated for hybrid normal-superconductor heterostructures with ultra-thin insulating barriers, where the transparency distribution is a bimodal function with two peaks at D = 0 and D = 1, and the difference between s- and d-wave superconductors is emphasized. The theoretical results are compared with our experimental shot-noise data for Nb/Al-AlOx-Nb junctions. To improve the signal to noise ratio of the measurement system the junctions dimensions have been reduced below 1 μm2 and measurement temperature below 2 K has been used. We have also studied double- barrier N1-I1-N2-I2-S structures as a model system for the transition from quantum (coherent) to classical (incoherent) regime of the charge transport and analyzed the impact of inelastic scatterings in the N2 interlayer on its shot-noise characteristics.

Shot noise in hybrid normal and superconducting multilayers / Lacquaniti, V; Belogolovskii, M; Callegaro, Luca; Cassiago, Cristina; DE LEO, Maria; Fretto, MATTEO ANDREA; Sosso, Andrea. - (2012), pp. 649-650. (Intervento presentato al convegno Applied Superconductivity Conference – ASC 2012 tenutosi a Portland (OR) nel October 7-12, 2012).

Shot noise in hybrid normal and superconducting multilayers

CALLEGARO, LUCA;CASSIAGO, CRISTINA;DE LEO, MARIA;FRETTO, MATTEO ANDREA;SOSSO, ANDREA
2012

Abstract

n coherent conducting multilayers with junction transparencies D comparable to unity, quantum fluc- tuations, which follow from the probabilistic nature of the backscattering restricted by the Pauli prin- ciple, are reduced in comparison to the standard Schottky result. Voltage dependence of the low- temperature shot noise is calculated for hybrid normal-superconductor heterostructures with ultra-thin insulating barriers, where the transparency distribution is a bimodal function with two peaks at D = 0 and D = 1, and the difference between s- and d-wave superconductors is emphasized. The theoretical results are compared with our experimental shot-noise data for Nb/Al-AlOx-Nb junctions. To improve the signal to noise ratio of the measurement system the junctions dimensions have been reduced below 1 μm2 and measurement temperature below 2 K has been used. We have also studied double- barrier N1-I1-N2-I2-S structures as a model system for the transition from quantum (coherent) to classical (incoherent) regime of the charge transport and analyzed the impact of inelastic scatterings in the N2 interlayer on its shot-noise characteristics.
2012
Applied Superconductivity Conference – ASC 2012
October 7-12, 2012
Portland (OR)
none
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11696/32302
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