Low-temperature thermal properties of mesoscopic normal-metal/superconductor heterostructures

Although the electrical transport properties of mesoscopic metallic samples have been investigated extensively over the past two decades, the thermal properties have received far less attention. This may be due in part to the difficulty of performing thermal measurements on submicron-scale samples. We report here quantitative measurements of the thermal conductance and thermopower of a hybrid normal-metal/superconductor heterostructure, which are made possible by the recent development of a local-thermometry technique. As with electrical transport measurements, these thermal measurements reveal signatures of the phase coherent nature of electron transport in these devices.