Thermoelectric Evidence of a Moiré Kondo Lattice

Thermoelectric transport coefficient directly links fundamental properties of materials (entropy and specific heat in particular) to voltage drops across the sample, which supplements electric transport measurement. In this talk, I will present a thermoelectric study of two-dimensional Kondo lattice material WSe₂/MoTe₂. The Seebeck and Nernst coefficients across a Kondo-breakdown transition are measured from 2K to 30K. The measured Seebeck coefficient undergoes a sign change when the Kondo lattice phase is destroyed by magnetic field or thermal fluctuation. The temperature at which Seebeck coefficient changes sign correlates with the Kondo crossover temperature, confirming the existence of a Kondo lattice. The method developed in this study can be applied to most two-dimensional systems.