title: Binding and interlayer force in the near-contact region of two graphite slabs: experiment and theory.
abstract: Via a novel experiment, Liu et al. [Phys. Rev. B 85, 205418 (2012)] estimated the graphite binding energy, specifically the cleavage energy, an important physical property of bulk graphite. We re-examine the data analysis and note that within the standard Lennard-Jones model employed, there are difficulties in achieving internal consistency in the reproduction of the graphite elastic properties. By employing similar models which guarantee consistency with the elastic constant, we find a wide range of model dependent binding energy values from the same experimental data. We attribute some of the difficulties in the determination of the binding energy to: (i) limited theoretical understanding of the van der Waals dispersion of graphite cleavage, (ii) the mis-match between the strong bending stiffness of the graphite-SiO2 cantilever and the weak asymptotic inter-layer forces that are integrated over to produce the binding energy. We find, however, that the data do support determination of a maximum inter-layer force that is relatively model independent. We conclude that the peak force per unit area is 1.1 ± 0.15 GPa for cleavage, and occurs at an inter-layer spacing of 0.377 ± 0.013 nm.
authors: Queensland Micro and Nano Technology Centre, Nathan Campus, Griffith University, 170 Kessels Road, Nathan, QLD 4111, Australia.
authors: Tim
authors: T
authors: Gould
authors: Department of Engineering Mechanics and Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China.
authors: Ze
authors: Z
authors: Liu
authors: Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia.
authors: Jefferson Zhe
authors: JZ
authors: Liu
authors: Queensland Micro and Nano Technology Centre, Nathan Campus, Griffith University, 170 Kessels Road, Nathan, QLD 4111, Australia.
authors: John F
authors: JF
authors: Dobson
authors: Department of Engineering Mechanics and Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China.
authors: Quanshui
authors: Q
authors: Zheng
authors: Laboratoire de Cristallographie, Résonance Magnétique et Modélisations (CRM2, UMR CNRS 7036) Institut Jean Barriol, Université de Lorraine BP 239, Boulevard des Aiguillettes, 54506 Vandoeuvre-lès-Nancy, France.
authors: S
authors: S
authors: Lebègue