All-Electronic Thermal Transport With Nonlocal Noise Thermometry in Graphene

Ever since the measurements of Wiedemann and Franz in 1853, thermal transport has played a central role in condensed matter physics. Thermal conductance can help pinpoint neutral modes such as spin waves, non-Fermi liquid states such as hydrodynamic states and Luttinger liquids, and topological degrees of freedom such as Majorana modes. In this context, van der Waals materials now offer a rich landscape of interacting, symmetry-broken, and topological states of matter enhanced by their low dimensionality, yet thermal transport has remained a difficult probe to realize for few-atom thick materials and for many of the most delicate electronic ground states. Here, we demonstrate a new technique to achieve all-electronic thermal transport in a van der Waals material. We use graphene as a sensitive electronic heater and thermometer by implementing a new type of nonlocal noise thermometry. We show that the technique allows us to accurately extract the electronic thermal conductance of a bridge between two graphene thermometers. This new probe now allows us to study a wide array of symmetry-broken and topological states in van der Waals materials through their heat transport properties.