Effects of interlayer screening and temperature on dielectric functions of graphene by first-principles

Journal Article · Thu Jul 21 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4959205· OSTI ID:22597765

Yang, J. Y. ^[1]

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1. School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

The dielectric functions of few-layer graphene and the related temperature dependence are investigated from the atomic scale using first-principles calculations. Compared with ellipsometry experiments in the spectral range of 190–2500 nm, the normalized optical constants of mono-layer graphene demonstrate good agreement and further validate first-principles calculations. To interpret dielectric function of mono-layer graphene, the electronic band structure and density of states are analyzed. By comparing dielectric functions of mono-, bi-, and tri-layer graphene, it shows that interlayer screening strengthens intraband transition and greatly enhances the absorption peak located around 1 eV. The strengthened optical absorption is intrinsically caused by the increasing electron states near the Fermi level. To investigate temperature effect, the first-principles calculations and lattice dynamics are combined. The lattice vibration enhances parallel optical absorption peak around 1 eV and induces redshift. Moreover, it is observed that the van der Waals force plays a key role in keeping the interlayer distance stable during dynamics simulations.

• OSTI ID: 22597765
• Journal Information: Journal of Applied Physics, Vol. 120, Issue 3; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
COMPARATIVE EVALUATIONS
DENSITY OF STATES
DIELECTRIC MATERIALS
ELLIPSOMETRY
ENERGY-LEVEL TRANSITIONS
FERMI LEVEL
GRAPHENE
LAYERS
PEAKS
RED SHIFT
SCREENING
TEMPERATURE DEPENDENCE
VAN DER WAALS FORCES