Active Electron Cooling of Graphene

In the emergent field of quantum technology, the ability to manage heat at the nanoscale and in cryogenic conditions is crucial for enhancing device performance in terms of noise, coherence, and sensitivity. Here, active cooling and refrigeration of the electron gas in graphene are demonstrated, by taking advantage of nanoscale superconducting tunnel contacts able to pump or extract heat directly from the electrons in the device. These structures achieved a top cooling of electrons in graphene of ∼15.5 mK at a bath temperature of ∼448 mK, demonstrating the viability of the proposed device architecture. These experimental findings are backed by a detailed thermal model that accurately replicated the observed behavior. Alternative cooling schemes and perspectives are discussed in light of the reported results. Finally, graphene electron cooling could find application in superconducting hybrid quantum technologies, such as radiation detectors, logic gates and qubits.