Isotopic effects in chair graphane

Abstract

Graphane is a layered material consisting of a sheet of hydrogenated graphene, with a C:H ratio of 1:1. We study isotopic effects in the properties of chair graphane, where H atoms alternate in a chairlike arrangement on both sides of the carbon layer. We use path-integral molecular dynamics simulations, which allows one to analyze the influence of nuclear quantum effects on equilibrium variables of materials. Finite-temperature properties of graphane are studied in the range 50--1500~K as functions of the isotopic mass of the constituent atoms, using an efficient tight-bonding potential. Results are presented for kinetic and internal energy, atomic mean-square displacements, fluctuations in the C--H bond direction, plus interatomic distances and layer area. At low temperature, substituting ${}^{13}$C for ${}^{12}$C gives a fractional change of $-2.6\times 10^{-4}$ in C--C distance and $-3.9\times 10^{-4}$ in the graphane layer area. Replacing ${}^2$H for ${}^1$H causes a larger fractional change in the C--H bond of $-5.7\times 10^{-3}$. The isotopic effect in C--C bond distance increases (decreases) by applying a tensile (compressive) in-plane stress. These results are interpreted in terms of a quasiharmonic approximation for the vibrational modes. Similarities and differences with isotopic effects in graphene are discussed.

arXiv comment17 pages, 11 figures, 2 tables

References in corpus (23)

• Control of graphene's properties by reversible hydrogenation
• Graphane: a two-dimensional hydrocarbon
• High-accuracy first-principles determination of the structural, vibrational and thermodynamical properties of diamond, graphite, and derivatives
• An accurate determination of the Avogadro constant by counting the atoms in a 28Si crystal
• Scaling Properties of Flexible Membranes from Atomistic Simulations: Application to Graphene
• Graphane Nanoribbons: A Theoretical Study
• Improved measurement results for the Avogadro constant using a 28Si-enriched crystal
• Monte Carlo study of the frame, fluctuation and internal tensions of fluctuating membranes with fixed area
• Isotope effects in ice Ih: A path-integral simulation
• Vibrational properties and diffusion of hydrogen on graphene
• Diffusion of hydrogen in graphite: A molecular dynamics simulation
• Kinetic energy of protons in ice Ih and water: a path integral study
• Quantum effects in graphene monolayers: Path-integral simulations
• Anharmonic effects in the optical and acoustic bending modes of graphene
• Diffusion of muonium and hydrogen in diamond
• Quantum and classical ripples in graphene
• Experimental Phonon Band Structure of Graphene using C${}^{12}andC$^{13}$ Isotopes
• Hydrogen and muonium in diamond: A path-integral molecular dynamics simulation
• Anharmonicity of the acoustic modes of graphene
• Isotope effects on the lattice parameter of cubic SiC
• Phonon dispersion in two-dimensional solids from atomic probability distributions
• Nuclear quantum effects in graphane
• Isotopic effects in structural properties of graphene

Cited by in corpus (1)

• Quantum effects in two-dimensional silicon carbide