On Topological Kondo Insulator Plasmonics

TL;DR

This paper investigates surface state plasmonics in topological Kondo insulators using a mean-field approach, revealing conditions for bulk insulation, surface metallicity, and the existence of intra- and inter-band plasmons.

Contribution

It introduces a mean-field slave-boson model for topological Kondo insulators that includes magnetic impurities and predicts plasmonic excitations on the surface.

Findings

Bulk insulation with surface metallicity is possible under strong f-electron localization.

Intra-band and inter-band acoustic plasmons can exist on gapped surface states.

Bulk metallicity dominates and plasmons have strong confinement capabilities.

Abstract

We study surface state plasmonics in the periodic Anderson model of a bulk topological Kondo insulator system, involving strongly correlated f electrons screened by weakly correlated d electrons, performing a mean-field theoretic calculation within the frame-work of slave-boson protocol. We include the effect of magnetic impurities as well which do not act as scattering agent in our scheme; the exchange interaction due to them is included in the band dispersion. The interaction opens a gap at the surface states with gapless Dirac dispersion. We find that bulk insulation together with the surface metallicity is possible for the system albeit only under the condition demanding strong f-electron localization. The possibility of the intra-band and the inter-band acoustic plasmons for the gapped surface states exists in our report. The dominance of the bulk metallicity and the strong incarceration capability of these plasmons are other notable outcome of the present work.