Disentangling electronic and phononic thermal transport across two-dimensional interfaces

Electrical and thermal transport at two-dimensional (2D) interfaces is critical for semiconductor technology, yet their interplay remains unclear. We report a theoretical proposal to separate electronic and phononic contributions to thermal conductance at 2D interfaces with graphene, which is validated by non-equilibrium Green’s function calculations and molecular dynamics simulations for graphene–gold contacts. Our results reveal that while metal–graphene interfaces are transparent for both electrons and phonons, non-covalent graphene interfaces block electronic tunneling beyond two layers but not phonon transport. This suggests that the Wiedemann–Franz law can be experimentally tested by measuring transport across interfaces with varying graphene layers.