Surface plasmons in doped topological insulators

Abstract

We investigate surface plasmons at a planar interface between a normal dielectric and a topological insulator, where the Fermi-energy lies inside the bulk gap of the topological insulator and gives rise to a two-dimensional charge distribution of free Dirac electrons. We develop the methodology for the calculation of plasmon dispersions, using the framework of classical electrodynamics, with modified constituent equations due to Hall currents in the topological insulator, together with a Lindhard-type description for the two-dimensional charge distribution of free Dirac electrons. For a system representative for Bi$_2$X$_3$ binary compounds, we find in agreement with recent related work that the modified constituent equations have practically no impact on the surface plasmon dispersion but lead to a rotation of the magnetic polarization of surface plasmons out of the interface plane.Comment: 5 pages, 2 figure

Plasmons in topological insulator cylindrical nanowires

“…We recall that, in TI, Hall currents can lead to a magnetoelectric effect according to which a magnetic field can induce a charge polarization. As a consequence, the separation between TE and TM is not exact in TI cylinders for l=0 38,39 . However, the magneto-electric effect can be treated at a perturbative level and have practically no impact on the plasmon properties of TI systems.…”

Tunable THz surface plasmon polariton based on a topological insulator/layered superconductor hybrid structure

“…The dielectric function of the chiral gapless topological insulator surface has been reported in [24,25,27], where, for the Hamiltonian for a 2D helical Dirac electron gas H 0 ,…”

“…Equation (9) can be calculated either analytically [10,27] or numerically, thanks to the identical expression of the polarization operator within the RPA for a simple Dirac gas and a helical Dirac gas. In our approach, we choose T = 10 K for numerical integration to avoid discontinuity, and compare with analytical result with at least six-digit agreement.…”

“…In order to solve the SPP loss problem, low-loss plasmonics based on graphene [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] and topological insulators (TIs) [24][25][26][27][28][29][30][31] has attracted much recent attention. In far-infrared and THz range, the major loss mechanism in graphene lies in the scattering between electrons and optical phonons [11].…”

Dynamic conductivity of the bulk states of n-type HgTe/CdTe quantum well topological insulator

“…6 There has been a myriad of research, both experimentally and theoretically, focusing on electron transports of the surface and bulk state of TIs. [13][14][15][16][17][18][19] However, when proceeding transport measurements of the topological edge or surface, the bulk response would significantly interrupt the surface signal. The response from the bulk would certainly be annoying if one cannot distinguish the different between the edge or surface and bulk.…”