First principles study on thermal conductivity of nitrogen substituted diamane

Abstract

2D materials have been in the spotlight due to their impressive properties since graphene was successfully synthesized. A single-layered diamond or diamane, which has high thermal conductivity and high stiffness inherited from its bulk counterpart, is a candidate for heat dissipating applications in nanodevices. Unfortunately, non-passivated dangling bonds on the surface of pristine diamane can cause its structural instability. Recent theoretical studies have suggested that site-specific substitution of N for C could stabilize the diamane’s structure without surface termination. Beside its superhard properties inherited from bulk carbon nitrides, thermal properties of N-substituted diamane have not been revealed. In this work, we investigate thermal properties of N-substituted diamane through first principles study. Our results show that there is an emergence of flexural phonon branch, which is regularly seen in 2D materials, and it contributes large thermal conductivity to N-substituted diamane. The thermal conductivity of N-substituted diamane is decreasing as the temperature increasing. At room temperature, it is 33% lower than that of diamond and 15-35% higher than that of hydrogen passivated diamane (H-diamane).