Heat-mode excitation in a proximity superconductor

Abstract

Mesoscopic superconductivity deals with various quasiparticle excitation modes, only one of them -- the charge-mode -- being directly accessible for conductance measurements due to the imbalance in populations of quasi-electron and quasihole excitation branches. Other modes carrying heat or even spin, valley etc. currents populate the branches equally and are charge-neutral, which makes them much harder to control. This noticeable gap in the experimental studies of mesoscopic non-equilibrium superconductivity can be filled by going beyond the conventional DC transport measurements and exploiting spontaneous current fluctuations. Here, we perform such an experiment and investigate the transport of heat in an open hybrid device based on a superconductor proximitized InAs nanowire. Using shot noise measurements, we investigate sub-gap Andreev heat guiding along the superconducting interface and fully characterize it in terms of the thermal conductance on the order of $G_{\mathrm{th}}\sim e^2/h$, tunable by a back gate voltage. Understanding of the heat-mode also uncovers its implicit signatures in the non-local charge transport. Our experiments open a direct pathway to probe generic charge-neutral excitations in superconducting hybrids.

as published; preprint format; 45 pages together with supplemental materials

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Cited by in corpus (10)

• Nonlocal measurement of quasiparticle charge and energy relaxation in proximitized semiconductor nanowires using quantum dots
• Quantum Hall Bogoliubov Interferometer
• Heat-charge separation in a hybrid superconducting quantum Hall setup
• Fate of the superconducting state in floating islands of hybrid nanowire devices
• $\Delta T$-noise in Multiterminal Hybrid Systems
• Thermal properties of the superconductor-quantum Hall interfaces
• Local thermometry of NbSe${}_2$ flake with delta-$T$ noise measurements
• Conductance measurements cannot distinguish crossed Andreev reflection from elastic co-tunneling in normal--superconductor--normal junctions
• Efficient Cooper Pair Splitting Without Interactions
• Microwave radiometry of a quantum-critical, hybrid Josephson array