The effect of rippling on the mechanical properties of graphene
arXiv:2106.16230 · doi:10.1016/j.nanoms.2021.05.005
Abstract
Graphene is the stiffest material known so far but, due to its one-atom thickness, it is also very bendable. Consequently, free-standing graphene exhibit ripples that has major effects on its elastic properties. Here we will summarize three experiments where the influence of rippling is essential to address the results. Firstly, we observed that atomic vacancies lessen the negative thermal expansion coefficient of free-standing graphene. We also observed an increase of the Young's modulus with global applied strain and with the introduction of small density defects that we attributed to the decrease of rippling. Here, we will focus on a surprising feature observed in the data: the experiments consistently indicate that only the rippling with wavelengths between 5-10nm influences the mechanics of graphene. The rippling responsible of the negative TEC and anomalous elasticity is thought to be dynamic, i.e. flexural phonons. However, flexural phonons with these wavelengths should have minor effects on the mechanics of graphene, therefore other mechanisms must be considered to address our observations. We propose static ripples as one of the key elements to correctly understand the thermomechanics of graphene and suggest that rippling arises naturally due to a competition of symmetry breaking and anharmonic fluctuations.
References in corpus (14)
- The Raman Fingerprint of Graphene
- The structure of suspended graphene sheets
- Probing the Nature of Defects in Graphene by Raman Spectroscopy
- Ripple Texturing of Suspended Graphene Atomic Membranes
- Negative Thermal Expansion Coefficient of Graphene Measured by Raman Spectroscopy
- High thermal conductivity of high-quality monolayer boron nitride and its thermal expansion
- Intrinsic and extrinsic corrugation of monolayer graphene deposited on SiO2
- Suppression of anharmonicities in crystalline membranes by external strain
- Electron-induced rippling in graphene
- Self-Consistent Screening Approximation for Flexible Membranes: Application to Graphene
- Hidden area and mechanical nonlinearities in freestanding graphene
- Thermal fluctuations of free standing graphene
- Indentation metrology of clamped, ultra-thin elastic sheets
- Nonlocal effective average action approach to crystalline phantom membranes