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Title: High temperature phonon dispersion in graphene using classical molecular dynamics

Phonon dispersion and phonon density of states of graphene are calculated using classical molecular dynamics simulations. In this method, the dynamical matrix is constructed based on linear response theory by computing the displacement of atoms during the simulations. The computed phonon dispersions show excellent agreement with experiments. The simulations are done in both NVT and NPT ensembles at 300 K and found that the LO/TO modes are getting hardened at the Γ point. The NPT ensemble simulations capture the anharmonicity of the crystal accurately and the hardening of LO/TO modes is more pronounced. We also found that at 300 K the C-C bond length reduces below the equilibrium value and the ZA bending mode frequency becomes imaginary close to Γ along K-Γ direction, which indicates instability of the flat 2D graphene sheets.
Authors:
;  [1] ;  [2]
  1. Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India)
  2. School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad-500046 (India)
Publication Date:
OSTI Identifier:
22269230
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1591; Journal Issue: 1; Conference: 58. DAE solid state physics symposium 2013, Patiala, Punjab (India), 17-21 Dec 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BOND LENGTHS; CRYSTALS; DENSITY; DISPERSIONS; GRAPHENE; HARDENING; INSTABILITY; MOLECULAR DYNAMICS METHOD; PHONONS; SIMULATION