Thursday, October 18, 2012

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


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

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.

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