Long-Range, Short-Wavelength and Ultrafast Heat Conduction driven by Three Plasmon Modes supported by Graphene

By leveraging the unique two-dimensional structure of graphene with its ability to support the propagation of surface plasmon-polaritons, we demonstrate the existence and propagation of three hybrid modes of surface plasmon polaritons supported by two graphene monolayers coating a solid film. These modes propagate long distances with short wavelengths, which are suitable features to enhance the heat conduction along the film interfaces. For a Si film with a thickness of 15 nm and a length of 5 mm at 300 K, we find a plasmon thermal conductivity of 13.6 Wm−1K−1, which represents 67% (26%) of its phonon Si (Si+graphene) counterpart. This thermal energy appears due to the coupling of plasmons propagating at speeds comparable to the speed of light in vacuum. The plasmonic heat conduction driven by two-dimensional materials thus appears as a major and unexpected mechanism for controlling temperature in solid-state systems without changing their internal structure and at rates faster than the ones of phonons and electrons.