Vibrational stability of graphene
Biao Wang (Sun Yat-sen University), Yulan Liu (Sun Yat-sen University)
Prager Medal Symposium in honor of George Weng: Micromechanics, Composites and Multifunctional Materials
Tue 9:00 - 10:30
MacMillan 117
The mechanical stability of graphene as temperature rises is analyzed based on three different self-consistent phonon (SCP) models. Compared with three-dimensional (3-D) materials, the critical temperature at which instability occurs for graphene is much closer to its melting temperature obtained from Monte Carlo simulation[20] ( ). This suggests that thermal vibration plays a significant role in melting of graphene while melting for 3-D materials is often dominated by topologic defects. The vibrational anisotropic coefficient (VAC) for graphene is defined upon its Lindermann ratios in different directions. Through analyzing the VAC it is found that the reason for the low of graphene is its high structural anisotropy. For any carbon based material with a graphene-like structure, the VAC value must be smaller than 5.4 to maintain its stability. We believe that the VAC can be regarded as a new criterion concerning the vibrational stability of any low-dimensional (low-D) materials.