Abstract: We propose the concept of thermal demultiplexer, which can split the heat flux in different frequency ranges into different directions. We demonstrate this device concept in a honeycomb lattice with dangling atoms. From the view of effective negative mass, we give a qualitative explanation of how the dangling atoms change the original transport property. We first design a two-mass configuration thermal demultiplexer, and find that the heat flux can flow into different ports in corresponding frequency ranges roughly. Then, to improve the performance, we choose the suitable masses of dangling atoms and optimize the four-mass configuration with genetic algorithm. Finally, we give out the optimal configuration with a remarkable effect. Our study finds a way to selectively split spectrum-resolved heat to different ports as phonon splitter, which would provide a new means to manipulate phonons and heat, and to guide the design of phononic thermal devices in the future.

Key words: phonon transport, thermal demultiplexer, optimization algorithm