Hot Carrier Thermalization and Josephson Inductance Thermometry in a Graphene-Based Microwave Circuit

Due to its exceptional electronic and thermal properties, graphene is a key material for bolometry, calorimetry, and photon detection. However, despite graphene's relatively simple electronic structure, the physical processes responsible for the heat transport from the electrons to the lattice are experimentally still elusive. Here, we measure the thermal response of low-disorder graphene encapsulated in hexagonal boron nitride by integrating it within a multiterminal superconducting microwave resonator. The device geometry allows us to simultaneously apply Joule heat power to the graphene flake while performing calibrated readout of the electron temperature. We probe the thermalization rates of both electrons and holes with high precision and observe a thermalization scaling exponent not consistent with cooling through the graphene bulk and argue that instead it can be attributed to processes at the graphene-aluminum interface. Our technique provides new insights into the thermalization pathways essential for the next-generation graphene thermal detectors.

Automated summary

Graphene is a crucial material for bolometry, calorimetry, and photon detection due to its exceptional electronic and thermal properties. However, the physical processes responsible for heat transport from electrons to lattice in graphene are still not well understood. In this study, researchers measured the thermal response of low-disorder graphene encapsulated in hexagonal boron nitride and integrated it within a multiterminal superconducting microwave resonator. Their findings suggest that the thermalization rates of electrons and holes in graphene can be attributed to processes at the graphene-aluminum interface.