3ω Method for Thermal Transport Studies in Two-Dimensional Materials

Thermal properties play a crucial role in investigating materials. However, it is difficult to measure thermal transport in atomically thin materials, due to the heat flow to any supporting substrate competing with that through a nanoscale sample. Motivated by a desire to measure thermal transport in 2D samples of α-RuCl₃, a candidate to host physics related to the Kitaev quantum spin liquid, we have developed an extension of the well-known 3ω method for measuring thermal transport appropriate for suspended atomically thin materials. This approach is able to extract the thermal conductivity and specific heat simultaneously by fitting to measurements of the complex thermal impedance vs frequency. We have benchmarked the method by measuring κ and C for suspended silicon nitride membranes, and will show recent results applying this method to measuring suspended α-RuCl₃ membranes.