Ab-initio study of thermal expansion in pure graphene

Journal Article · Mon May 23 04:00:00 EDT 2016 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4948059· OSTI ID:22608801

Mann, Sarita; Kumar, Ranjan; Rani, Pooja ^[1]

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1. D.A.V. College, Sec-10, Chandigarh-160010 (India)

Graphene is a zero band gap semiconductor with exceptionally high thermal conductivity. The electronic properties having been studied, therole of phonon in contributing to thermal expansion, thermal conductivity and other thermodynamic properties, is required to be investigated. This paper focuses more on thermal expansion. Some others results like phonon dispersion, Grüneisenparameters and bulk modulus,which are essential to estimation of thermal expansion, are also presented. The dynamical matrix was calculated using VASP code using both DFT and DFPT and the phonon frequencies were calculated using phonopy code under harmonic approximation. The linear thermal expansion coefficient of graphene is found to be strongly dependent on temperature but remains negative upto 470 K and positive thereafter, with a room temperature value of −1.44×10{sup −6}. The negative expansion coefficient is very interesting and is found to be in conformity with experimental as well as with recent theoretical estimates. There is only qualitative agreement of our results with experimental data and motivates further investigation, primarily on the high negative values of Grüneisen parameters.

• OSTI ID: 22608801
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1731; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
APPROXIMATIONS
DENSITY FUNCTIONAL METHOD
DISPERSIONS
GRAPHENE
PHONONS
SEMICONDUCTOR MATERIALS
SIMULATION
TEMPERATURE RANGE 0273-0400 K
THERMAL CONDUCTIVITY
THERMAL EXPANSION