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Jaime E. Santos: Renormalisation of nanoparticles’ polarisability in the vicinity of a graphene-covered interface

posted 28 Jul 2015, 05:12 by info admin
Jaime E. Santos 1, M. I. Vasilevskiy 2, N. M. R. Peres 2, G. Smirnov 2, Yu. V. Bludov 2
1- DTU Nanotech, Building 345B, Ørsteds Pl., 2800 Kongens Lyngby, Denmark 2- Centro de Fisica e Departamento de Fisica, Universidade do Minho, 4710-057 Braga, Portugal

We study the electromagnetic properties of a metamaterial consisting of polarisable (nano)-particles and a single graphene sheet placed at the interface between two dielectrics. We show that the particle's polarisability is renormalised because of the electromagnetic coupling to surface plasmons supported by graphene, which results in a dispersive behavior, different for the polarisability components corresponding to the induced dipole moment, parallel and perpendicular to the graphene sheet. In particular, this effect is predicted to take place for a metallic particle whose bare polarisability in the terahertz (THz) region is practically equal to the cube of its radius (times 4πε
0). This opens the possibility to excite surface plasmons in graphene and enhance its absorption in the THz range by simply using a monolayer of metallic particles randomly deposited on top of it, as we show by explicit calculations [1].

[1] Jaime E. Santos, M. I. Vasilevskiy, N. M. R. Peres, G. Smirnov, Yu. V. Bludov, Phys. Rev. B 90, 235420 (2014)

Jaime E. Santos received his degree in Physics from the University of Porto, Portugal, in 1993 and his DPhil in Theoretical Physics from the University of Oxford, in the UK, in 1997. Since then, he has held positions at the TUM in Munich, at the Hahn Meitner Institute in Berlin, and at the Universities of Porto and Minho in Portugal. Currently, he is a Guest Scientist at the CNG, DTU Nanotech, holding a position as Temporary Associate Professor (Lektor). His main interest is the Physics of Graphene and related two-dimensional materials, in particular the transport properties and the optical properties of such systems, but he has also interests in Non-Equilibrium Thermodynamics of Quantum Systems and the Physics of Solar Cells.