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Some recent trends in graphene: magneto-optics, plasmonics and spintronics in 2D

Speaker: 
Aires Ferreira (Graphene Centre, NUS)
Date: 
Wed, 28/08/2013 - 11:00am to 12:00pm
Location: 
S13-M01-11 (Physics Conference Room)
Event Type: 
Seminars

Abstract

With the advent of graphene and related two-dimensional crystals, a new playground for light-matter interactions, charge and spin transport has emerged. In the first part of the talk I overview recent results on graphene-based plasmonics; the unique electronic properties of graphene, characterized by massless and chiral low-energy excitations, and unconventional transport properties, originate the most distinct electromagnetic confinement behavior, such as plasmonic propagation lengths exceeding those of conventional metal-dielectric interfaces [1], and guided transverse-electric modes with tunable frequency [2]. The application of a quantizing magnetic field is shown to give rise to a rich electromagnetic mode spectrum with extended crossovers between quasi-transverse-electric and magnetoplasmon-polariton modes [3]. I also discuss how surface plasmons may be useful to overcome the major obstacle in graphene-based optoelectronics, i.e., the small light absorption in one-atom thick graphene. A hybrid graphene-metamaterial system is proposed, where, for the first time, enhanced light absorption is seen to take place in a single sheet of graphene [4]. Finally, in the last part of the talk, I present our recent studies predicting that giant pure spin Hall currents can be enginereed in graphene by decoration with small doses of adatoms, molecules or nano-particles originating local spin-orbit perturbations [5]. The exact treatment of the single impurity scattering problem shows that intrinsic and Rashba spin-orbit local couplings enhance the spin Hall current via skew scattering of charge carriers in the resonant regime. These findings suggest that functionalised graphene systems can be used to design spintronic integrated circuits with spin Hall effect-based spin-polarized current activation and control.

[1] M. Jablan, H. Buljan, and M. Soljacic, Phys. Rev. B 80, 245435 (2009).
[2] S. A. Mikhailov, and K. Ziegler, Phys. Rev. Lett. 99, 016803 (2007).
[3] A. Ferreira, N. M. R. Peres, and A. H. Castro Neto, Phys. Rev. B 85, 205426 (2012).
[4] A. Ferreira, and N. M. R. Peres, Phys. Rev. B 86, 205401 (2012).
[5] A. Ferreira, T. G. Rappoport, M. A. Cazalilla, and A. H. Castro Neto, Pre-Print arXiv:1304.7511 (2013).

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