Thermal properties and overheating of the superconductor-quantum Hall interfaces

Low-frequency noise measurements have been successfully used to probe such phenomena as the fractional charges and the quanta of heat conduction of fermions or anyons in the quantum Hall (QH) regime. Here we study the excess noise at the interface of a superconducting film and an encapsulated graphene in the QH regime. We find that the primary source of the excess noise is local heating, which allows one to convert the noise to electron temperature using Johnson-Nyquist noise calibration. As the magnetic field is increased, the temperature of the interface is reduced, eventually approaching the behavior expected for a normal metal. We further use our sample to study the heat conductivity across the superconducting film subject to a high magnetic field.