High intrinsic lattice thermal conductivity in monolayer MoSi2N4

Very recently, a novel two-dimension (2D) MXene, MoSi2N4, was successfully synthesized with excellent ambient stability, high carrier mobility, and moderate band gap (2020 Science 369 670). In this work, the intrinsic lattice thermal conductivity of monolayer MoSi2N4 is predicted by solving the phonon Boltzmann transport equation based on the first-principles calculations. Despite the heavy atomic mass of Mo and complex crystal structure, the monolayer MoSi2N4 unexpectedly exhibits a quite high lattice thermal conductivity over a wide temperature range between 300 to 800 K. At 300 K, its in-plane lattice thermal conductivity is 224 Wm(-1) K-1. The detailed analysis indicates that the large group velocities and small anharmonicity are the main reasons for its high lattice thermal conductivity. We also calculate the lattice thermal conductivity of monolayer WSi2N4, which is only a little smaller than that of MoSi2N4. Our findings suggest that monolayer MoSi2N4 and WSi2N4 are potential 2D materials for thermal transport in future nano-electronic devices.

Automated summary

A novel 2D MXene, MoSi2N4, with excellent ambient stability, high carrier mobility, and moderate band gap was successfully synthesized recently. The monolayer MoSi2N4 was found to unexpectedly exhibit high lattice thermal conductivity, making it a potential material for thermal transport in future nano-electronic devices. Despite its heavy atomic mass and complex crystal structure, MoSi2N4 showed high lattice thermal conductivity due to large group velocities and small anharmonicity.