Quasi-one-dimensional thermal transport in trigonal selenium crystal

The lattice thermal conductivity in van der Waals crystal selenium is investigated by solving the phonon Boltzmann transport equation combined with the first-principles calculations. The lattice thermal conductivity of selenium along the perpendicular to the chain direction is extremely low, which is 5 times lower than the conductivity in the parallel direction, showing a clear quasi-one-dimensional heat transfer feature. The small phonon group velocity, acoustic-optical phonon branches mixing and bonding anharmonicity along the perpendicular to the chain direction contribute to the high anisotropy in thermal conductivity. Moreover, particles with several nanometers can introduce boundary scattering to a large portion of phonons modes in selenium, where the lattice thermal conductivity is greatly reduced. Both the unique one-dimensional thermal transport property and low thermal conductivity make selenium to be a potential thermal management in thermoelectric and other electronic technologies.

Automated summary

The lattice thermal conductivity of van der Waals crystal selenium exhibits significant anisotropy, with the conductivity along the perpendicular to the chain direction being much lower than in the parallel direction, indicating quasi-one-dimensional heat transfer. Factors such as small phonon group velocity, mixing of acoustic-optical phonon branches, and bonding anharmonicity contribute to the high anisotropy in thermal conductivity in selenium. Additionally, the introduction of nanoparticles can greatly reduce the lattice thermal conductivity by introducing boundary scattering to a large portion of phonon modes.