Two-Dimensional Glass Transition in Graphene: Insights from Molecular Simulations
R. Ravinder1, Rajesh Kumar1, Manish Agarwal2, N. M. Anoop Krishnan1,3*
1Department of Civil Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
2Computer Services Center, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
3Department of Materials Science and Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
*Corresponding author: krishnan[at]iitd.ac.in
When liquid is cooled fast enough, it avoids crystallization and form a disordered structure known as glasses. This phenomenon is known as glass transition. Extensive studies have been conducted on model materials to understand glass transition in two dimensions. However, despite the synthesis of disordered/amorphous single-atom thick structures of carbon, little attention has been given to glass transition in realistic two-dimensional materials such as graphene. In the present work, using atomistic simulations, we demonstrate the existence of a two-dimensional glass transition in graphene leading to a realistic disordered structure. The resulting disordered structure exhibits close match with experimentally obtained disordered graphene. We show that the glassy graphene exhibits a wrinkled, but highly stable structure. Interestingly, we observe that the defects in glassy graphene control the structural vibrations by acting as pseudo-supports locally. Overall, the study suggests that the defect engineering of glassy graphene can be exploited to develop novel two-dimensional glasses with superior mechanical properties for practical applications.
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