Lattice thermal properties of Graphane: thermal contraction, roughness and heat capacity

TL;DR

This study uses atomistic simulations to analyze the thermal contraction, roughness, ripples, and heat capacity of suspended graphane, revealing significant differences from graphene, including larger heat capacity and distinct ripple characteristics.

Contribution

The paper provides the first detailed atomistic simulation analysis of the thermal and roughness properties of suspended graphane, highlighting its differences from graphene.

Findings

Graphane exhibits larger thermal contraction than graphene.

The roughness exponent of graphane at room temperature is approximately 1.0.

Heat capacity of graphane is about 14.8% larger than graphene.

Abstract

Using atomistic simulations we determine the roughness and the thermal properties of a suspended graphane sheet. As compared to graphene we found that hydrogenated graphene has: 1) a larger thermal contraction, 2) the roughness exponent at room temperature is smaller, i.e. $\simeq$ 1.0 versus $\simeq$ 1.2 for graphene, 3) the wave lengths of the induced ripples in graphane cover a wide range corresponding to length scales in the range (30-125)\,\AA at room temperature, and 4) the heat capacity of graphane is estimated to be 29.32$\pm$0.23\,J/molK which is 14.8% larger than the one for graphene, i.e. 24.98$\pm$0.14\,J/molK. Above 1500\,K we found that graphane buckles when its edges are supported in the $x-y$ plane.