Effect of uni-axial strain on THz/far-infrared response of graphene

Abstract

We present polarized optical transmission study of uniaxially strained large scale graphene in THz/far-infrared (IR) frequency region. Graphene was supported on stretchable polyethylene substrate and they were elongated up to 20% (Delta(L)/L-o=0.2) by applying tensile force. For the IR light polarized along the strain direction (E-IR//strain), the optical conductivity sigma(1)(omega) of graphene changes from Drude response into strongly non-Drude-like behavior with a peak formed at finite energy similar to 10 meV. In contrast, the coherent Drude conductivity is preserved along the direction perpendicular to the strain (E-IR perpendicular to strain). Possible origin of the strain-induced non-Drude sigma(1)(omega)-behavior is discussed. (C) 2012 American Institute of Physics. [doi:10.1063/1.3680095]