Spin-charge separation of plasmonic excitations in thin topological insulators

Abstract

We discuss plasmonic excitations in a thin slab of a topological insulators. In the limit of no hybridization of the surface states and same electronic density of the two layers, the electrostatic coupling between the top and bottom layers leads to optical and acoustic plasmons which are purely charge and spin collective oscillations. We then argue that a recent experiment on the plasmonic excitations of Bi2Se3 [Di Pietro et al, Nat. Nanotechnol. 8, 556 (2013)] must be explained by including the charge response of the two-dimensional electron gas of the depletion layer underneath the two surfaces. We also present an analytic formula to fit their data.

7 pages, 5 figures

References in corpus (10)

• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Dielectric function, screening, and plasmons in 2D graphene
• Dynamical polarization of graphene at finite doping
• Realization of a High Mobility Dual-gated Graphene Field Effect Transistor with Al2O3 Dielectric
• Mid-infrared plasmons in scaled graphene nanostructures
• Coexistence of the topological state and a two-dimensional electron gas on the surface of Bi2Se3
• Observation of Dirac plasmons in a topological insulator
• Coulomb drag between massless and massive fermions
• Plasmons in layered structures including graphene
• Charge and spin density response functions of the clean two-dimensional electron gas with Rashba spin-orbit coupling at finite momenta and frequencies

Cited by in corpus (20)

• Plasmonics in Dirac systems: from graphene to topological insulators
• Strong nonlinear terahertz response induced by Dirac surface states in Bi2Se3 Topological Insulator
• Chiral response of twisted bilayer graphene
• Topological insulators are tunable waveguides for hyperbolic polaritons
• Plasmonics in topological insulators: Spin-charge separation, the influence of the inversion layer, and phonon-plasmon coupling
• Universal features of the optical properties of ultrathin plasmonic films
• Propagation of Surface Plasmon Polaritons in Thin Films of Topological Insulators
• Surface plasmon polaritons in topological insulator
• Transmission Line Model for Materials with Spin-Momentum Locking
• Controlling surface charge and spin density oscillations by Dirac plasmon interaction in thin topological insulators
• Phonon-mediated strong coupling between a three-dimensional topological insulator and a two-dimensional antiferromagnetic material
• Real-space nanoimaging of THz polaritons in the topological insulator Bi2Se3
• Collective excitations of a system of coupled relativistic and non-relativistic two-dimensional electron gases
• Tunable THz Surface Plasmon Polariton based on Topological Insulator-Layered Superconductor Hybrid Structure
• Control of Plasmons in Topological Insulators via Local Perturbations
• In-Plane Plasmon Coupling in Topological Insulator Bi${}_2$Se${}_3$ Thin Films
• Control of 2D plasmons in the topological insulator Bi2Se3 with highly crystalline C60 overlayers
• Dynamical density response and collective modes of topological insulator ultra-thin films
• Equatorial magnetoplasma waves
• Plasmons in semiconductor and topological insulator wires with large dielectric constant