Berlin 2018 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 13: Graphene: Electronic Properties, Structure and Substrate Interaction I (joint session O/TT)

TT 13.6: Talk

Monday, March 12, 2018, 11:45–12:00, MA 043

Light-field-driven currents in graphene — •Christian Heide, Takuya Higuchi, Konrad Ullmann, Heiko B. Weber, and Peter Hommelhoff — Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen

Strong-field physics centres on controlling the motion of electrons by virtue of an optical electric field with attosecond (10⁻¹⁸ s) precision. Graphene is an ideal playground for extending the scope of strong-field phenomena to a conductor because of its excellent carrier mobility, much weaker screening due to a low carrier concentration compared with conventional metals and its ultrafast and broadband optical response.

We will show that one can control the residual conducting current in epitaxially grown graphene by tailoring the electric-field waveform of few-cycle laser pulses, on attosecond timescales [1]. We interpret the waveform-dependent conducting current by considering graphene as a simple two-band system, interacting with an oscillating optical field of an ultrashort laser pulse. We found a transition from the weak, perturbative nonlinear response (photon-driven) to optical-field-driven, non-perturbative electron dynamics, in which the influence of the intraband dynamics to the interband transition cannot be neglected. Inthis strong-field regime, electrons exhibit quantum-mechanical interference known as Landau-Zener-Stückelberg interference.

[1] T. Higuchi, C. Heide, K. Ullmann, H. B. Weber, and P. Hommelhoff, Light-field-driven currents in graphene, Nature 550, 224 (2017).