Electrons with a linear energy/momentum dispersion are called massless Dirac electrons and represent the low-energy excitations in exotic materials such as graphene and topological insulators. Dirac electrons are characterized by notable properties such as a high mobility, a tunable density and, in topological insulators, a protection against backscattering through the spin-momentum locking mechanism. All those properties make graphene and topological insulators appealing for plasmonics applications. However, Dirac electrons are expected to present also a strong nonlinear optical behaviour. This should mirror in phenomena such as electromagnetic-induced transparency and harmonic generation. Here we demonstrate that in Bi2Se3 topological insulator, an electromagnetic-induced transparency is achieved under the application of a strong terahertz electric field. This effect, concomitantly determined by harmonic generation and charge-mobility reduction, is exclusively related to the presence of Dirac electron at the surface of Bi2Se3, and opens the road towards tunable terahertz nonlinear optical devices based on topological insulator materials.

Giorgianni, F., Chiadroni, E., Rovere, A., Cestelli Guidi, M., Perucchi, A., Bellaveglia, M., et al. (2016). Strong nonlinear terahertz response induced by Dirac surface states in Bi2Se3 topological insulator. NATURE COMMUNICATIONS, 7, 11421 [10.1038/ncomms11421].

Strong nonlinear terahertz response induced by Dirac surface states in Bi2Se3 topological insulator

CIANCHI, ALESSANDRO;
2016-04-26

Abstract

Electrons with a linear energy/momentum dispersion are called massless Dirac electrons and represent the low-energy excitations in exotic materials such as graphene and topological insulators. Dirac electrons are characterized by notable properties such as a high mobility, a tunable density and, in topological insulators, a protection against backscattering through the spin-momentum locking mechanism. All those properties make graphene and topological insulators appealing for plasmonics applications. However, Dirac electrons are expected to present also a strong nonlinear optical behaviour. This should mirror in phenomena such as electromagnetic-induced transparency and harmonic generation. Here we demonstrate that in Bi2Se3 topological insulator, an electromagnetic-induced transparency is achieved under the application of a strong terahertz electric field. This effect, concomitantly determined by harmonic generation and charge-mobility reduction, is exclusively related to the presence of Dirac electron at the surface of Bi2Se3, and opens the road towards tunable terahertz nonlinear optical devices based on topological insulator materials.
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin)
Settore FIS/01 - Fisica Sperimentale
English
THz; insulator
Giorgianni, F., Chiadroni, E., Rovere, A., Cestelli Guidi, M., Perucchi, A., Bellaveglia, M., et al. (2016). Strong nonlinear terahertz response induced by Dirac surface states in Bi2Se3 topological insulator. NATURE COMMUNICATIONS, 7, 11421 [10.1038/ncomms11421].
Giorgianni, F; Chiadroni, E; Rovere, A; Cestelli Guidi, M; Perucchi, A; Bellaveglia, M; Castellano, M; Di Giovenale, D; Di Pirro, G; Ferrario, M; Pompili, R; Vaccarezza, C; Villa, F; Cianchi, A; Mostacci, A; Petrarca, M; Brahlek, M; Koirala, N; Oh, S; Lupi, S
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2108/142907
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