Room temperature thermal switching based on monolayer boron nitride

The research for materials capable of manipulating thermal conductivity continues to fuel the development of thermal controlling devices. Here, using ab initio calculations and Boltzmann transport equation, we demonstrate that the thermal conductivity of semi-fluorinated h-BN can be reversibly manipulated at 300 K, and the ratio on the regulation of thermal conductivity reaches up to 11.23. Such behavior originates from the high sensitivity of thermal conductivity to the magnetic ordering. Semi-fluorinated h-BN is a paramagnetic material at room temperature due to its Curie temperature of 270 K. Impressively, semi-fluorinated h-BN can be modulated as a ferromagnetic system by adding an external magnetic field of 11.15 T, resulting in the greatly and reversibly tunable thermal conductivity at room temperature. Furthermore, the in-depth analyses of phonon properties show that compared with the paramagnetic phase, the ferromagnetic and antiferromagnetic semi-fluorinated h-BN significantly reduces the phonon scattering and anharmonicity, thereby enhancing the thermal conductivity. The results qualify semi-fluorinated h-BN as a potential candidate for thermal switching applications at room temperature.