Abstract-Ultrafast Carrier Dynamics in Graphene under a High Electric Field

http://prl.aps.org/abstract/PRL/v109/i16/e166603

Shuntaro Tani^1,2,*, François Blanchard^2,3, and Koichiro Tanaka^1,2,3,†

¹Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
²CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan

³Institute for Integrated Cell-Material Sciences (WPI-iCeMS),Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan

We investigated ultrafast carrier dynamics in graphene with near-infrared transient absorption measurement after intense half-cycle terahertz pulse excitation. The terahertz electric field efficiently drives the carriers, inducing large transparency in the near-infrared region. Theoretical calculations using the Boltzmann transport equation quantitatively reproduce the experimental findings. This good agreement suggests that the intense terahertz field should promote a remarkable impact ionization process and increase the carrier density.