Intrinsically low lattice thermal conductivity of monolayer hexagonal aluminum nitride (h-AlN) from first-principles: A comparative study with graphene

Abstract

Stimulated by the research progress of graphene, lots of more graphene-like two-dimensional (2D) materials are well-explored in both theoretical and experimental studies for the potential applications in electronics, where high-performance thermal management plays a key role. In this paper, we performed the state-of-art first-principles study on the thermal transport properties of monolayer h-AlN, which is a typical graphene-like 2D III-V compound with planar honeycomb structure and excellent electronic properties. It is found that h-AlN possesses a much lower thermal conductivity (73.43 W/mK at 300 K) compared to graphene (3094.98 W/mK). Detailed comparative analysis is presented in terms of mode level group velocity, scattering phase space (channel), and phonon anharmonicity. Furthermore, the electronic structures of h-AlN reveal the existence of isolated electron pairs, which play a key role in enhancing the orbit-driven strong anharmonicity and leading to the low thermal conductivity. The in-depth analysis of the low thermal conductivity of h-AlN sheds a light on future studies of thermal management materials.