${\Delta }_T$ Noise in Mesoscopic Hybrid Junctions: Influence of Barrier Strength and Thermal Bias

Abstract

Quantum noise is a fundamental probe of quantum transport phenomena, offering insights into current correlations and wave-particle duality. A particularly intriguing form of such noise, ${\Delta }_T$ noise, emerges under a finite temperature difference in the absence of charge current at zero voltage bias. In this work, we investigate ${\Delta }_T$ noise in mesoscopic hybrid junctions incorporating insulating barriers, where the average charge current remains zero at zero bias. Using quantum shot noise measurements, we demonstrate that ${\Delta }_T$ noise in metal-insulator-superconductor (NIS) junctions is approximately $16$ times greater than in metal-insulator-metal (NIN) counterparts. Our analysis further reveals that ${\Delta }_T$ noise exhibits a non-monotonic dependence on barrier strength, rising to a peak before declining, while increasing monotonically with the applied temperature bias. These findings underscore the rich interplay between thermal gradients and barrier properties in determining quantum noise characteristics in hybrid mesoscopic systems.

arXiv comment19 pages, 6 figures, accepted for publication in J. Phys. Condensed Matter (2025)

References in corpus (18)

• Shot Noise in Mesoscopic Conductors
• Scanning tunneling spectroscopy of high-temperature superconductors
• Fundamental aspects of steady-state conversion of heat to work at the nanoscale
• Quantum limit of heat flow across a single electronic channel
• Gauge invariant nonlinear electric transport in mesoscopic conductors
• Heat Transport in Mesoscopic Systems
• Scattering theory of nonlinear thermoelectric transport
• Nonlinear heat transport in mesoscopic conductors: Rectification, Peltier effect and Wiedemann-Franz law
• Onset of a Pseudogap Regime in Ultracold Fermi Gases
• Scattering Theory of Nonlinear Thermoelectricity in Quantum Coherent Conductors
• Electronic heat flow and thermal shot noise in quantum circuits
• Negative delta-$T$ noise in the Fractional Quantum Hall effect
• Shot Noise of a Temperature-Biased Tunnel Junction
• Charge, spin, and heat shot noises in the absence of average currents: Conditions on bounds at zero and finite frequencies
• Scattering Theory of Non-Equilibrium Noise and Delta $T$ current fluctuations through a quantum dot
• Smooth, homogeneous, high-purity Nb3Sn superconducting RF resonant cavity by seed-free electrochemical synthesis
• Why shot noise does not generally detect pairing in mesoscopic superconducting tunnel junctions
• Machine learning delta-T noise for temperature bias estimation