Using atomistic simulations, we determine the roughness and the thermal properties of a suspended graphane sheet. As compared to graphene, we found that (i) hydrogenated graphene has a larger thermal contraction, (ii) the roughness exponent at room temperature is smaller, i.e., $\simeq$ 1.0 versus $\simeq$ 1.2 for graphene, (iii) the wavelengths of the induced ripples in graphane cover a wide range corresponding to length scales in the range 30–125 Å at room temperature, and (iv) the heat capacity of graphane is estimated to be $29.32\pm 0.23$ J/mol K, which is $14.8\%$ larger than that for graphene, i.e., $24.98\pm 0.14$ J/mol K. Above 1500 K, we found that graphane buckles when its edges are supported in the $x-y$ plane.

• Received 10 May 2011

DOI:https://doi.org/10.1103/PhysRevB.83.235437