Abstract
Diamond-derived two-dimensional (2D) materials or diamanes show promising properties such as high elastic constants and giant thermal conductivity. We here present a new phase of diamane variants, AA-NCCN, which is a diamane-like structure of two carbon nitride layers in AA-stacking. Its thermal conductivity is higher than that of AB-NCCN, which is an AB-stacking configuration of NCCN, and hydrogenated diamane, computed by the relaxation time approximation (RTA) method. Because the RTA underestimates the thermal conductivity of some 2D materials, we propose that AA-NCCN could be a candidate whose thermal conductivity rivals that of diamond and a coexisting phase with AB-NCCN.