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Tuning and Persistent Switching of Graphene Plasmons on a Ferroelectric Substrate

M. D. Goldflam, G. Ni, K. W. Post, Z. Fei, Y. Yeo, J. You Tan, A. S. Rodin, B. C. Chapler, B. Özyilmaz, A. H. Castro Neto, M. M. Fogler and D. N. Basov

Nano Letters, 15 (8), pp 4859–4864 (2015)
We characterized plasmon propagation in graphene on thin films of the high-κ dielectric PbZr0.3Ti0.7O3 (PZT). Significant modulation (up to ±75%) of the plasmon wavelength was achieved with application of ultrasmall voltages (< ±1 V) across PZT. Analysis of the observed plasmonic fringes at the graphene edge indicates that carriers in graphene on PZT behave as noninteracting Dirac Fermions approximated by a semiclassical Drude response, which may be attributed to strong dielectric screening at the graphene/PZT interface. Additionally, significant plasmon scattering occurs at the grain boundaries of PZT from topographic and/or polarization induced graphene conductivity variation in the interior of graphene, reducing the overall plasmon propagation length. Lastly, through application of 2 V across PZT, we demonstrate the capability to persistently modify the plasmonic response of graphene through transient voltage application.