Observation of Magnetoplasmons in Bi2Se3 Topological Insulator

Marta Autore, Hans Engelkamp, Fausto D'Apuzzo, Alessandra Di Gaspare, Paola Di Pietro, Irene Lo Vecchio, Matthew Brahlek, Nikesh Koirala, Seongshik Oh, Stefano Lupi

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

Both the collective (plasmon) and the single particle (Drude) excitations of an electron gas can be controlled and modified by an external magnetic field B. At finite B, plasmon gives rise to a magnetoplasmon mode and the Drude term to a cyclotron resonance. These magnetic effects are expected to be extremely strong for Dirac electrons with a linear energy-momentum dispersion, like those present in graphene and topological insulators (TIs). Here, we investigate both the plasmon and the Drude response versus B in Bi2Se3 topological insulator. At low B, the cyclotron resonance is still well separated in energy from the magnetoplasmon mode; meanwhile, both excitations asymptotically converge at the same energy for increasing B, consistently with a dynamical mass for Dirac carriers of (Formula presented.) = 0.18 ± 0.01 me. In TIs, one then achieves an excellent magnetic control of plasmonic excitations and this could open the way toward plasmon controlled terahertz magneto-optics.

Original languageEnglish (US)
Pages (from-to)1231-1235
Number of pages5
JournalACS Photonics
Volume2
Issue number9
DOIs
StatePublished - Aug 20 2015

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Biotechnology
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

Keywords

  • Dirac carriers
  • cyclotron resonance
  • dynamical mass
  • plasmons
  • topological insulators

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