Optical Conductivity of Strained Graphene

Date

Mar 7, 2017

Time

10:30 AM - 11:30 AM

Speaker

Viktor Könye

Affiliation

Eötvös Loránd University, Budapest

Language

en

Main Topic

Materialien

Other Topics

Materialien, Physik

Host

Grit Rötzer

Description

We study the optical conductivity of graphene using the Kubo formula in the framework of linear response theory. The formalism is used to describe affine transformed honeycomb lattices. The band structure of strained graphene (isotropic compressive, uniaxial and shear strain) is calculated in the tight binding model. Using the Kubo formula a compact analytic expression is derived, with which the optical conductivity can be evaluated by numerical line integration over energy contours. The optical conductivity is studied as a function of the frequency of the incident light. We show that the singular behaviour in the conductivity spectra is directly related to the Van-Hove singularities in the density of states. In the unstrained graphene the energies at the M points of the Brillouin zone are degenerated, but in the strained case these degenerations are lifted and this leads to the splitting of the peaks in the optical conductivity spectra. Our formalism can be used to describe other two-dimensional materials, e.g. bilayer graphene, silicene or the Dirac-Weyl system. .

Links

• Seminars at the IFW

Last modified: Mar 7, 2017, 8:47:16 AM