Surface Theory of a Family of Topological Kondo Insulators

Abstract

A low-energy theory for the helical metallic states, residing on the surface of cubic topological Kondo insulators, is derived. Despite our analysis being primarily focused on a prototype topological Kondo insulator, Samarium hexaboride (SmB${}_6$), the surface theory derived here can also capture key properties of other heavy fermion topological compounds with a similar underlying crystal structure. Starting from an effective mean-field eight-band model in the bulk, we arrive at a low-energy description of the surface states, pursuing both analytical and numerical approaches. In particular, we show that helical Dirac excitations occur near the $\bar{\Gamma }$ point and the two $\bar{X}$-points of the surface Brillouin zone and generally the energies of the Dirac points display {\it offset} relative to each other. We calculate the dependence of several observables (such as bulk insulating gap, energies of the surface Dirac fermions, their relative position to the bulk gap, etc.) on various parameters in the theory. We also investigate the effect of a spatial modulation of the chemical potential on the surface spectrum and show that this band bending generally results in "dragging down" of the Dirac points deep into the valence band and strong enhancement of Fermi velocity of surface electrons. Comparisons with recent ARPES and quantum oscillation experiments are drawn.

14 Pages, 8 Figures: Published version with slightly revised discussion, typos corrected

References in corpus (7)

• Coexistence of the topological state and a two-dimensional electron gas on the surface of Bi2Se3
• Correlated Topological Insulators with Mixed Valence
• Emergent quantum confinement at topological insulator surfaces
• Direct observation of the spin texture in strongly correlated SmB6 as evidence of the topological Kondo insulator
• Hybridization, Inter-Ion Correlation, and Surface States in the Kondo Insulator SmB6
• Angle-resolved Photoemission Spectroscopy Study on the Surface States of the Correlated Topological Insulator YbB6
• End states in a 1-D topological Kondo insulator

Cited by in corpus (13)

• Interaction Driven Subgap Spin Exciton in the Kondo Insulator SmB6
• Surface state reconstruction in ion-damaged SmB_6
• In-gap collective mode spectrum of the Topological Kondo Insulator SmB6
• Two-dimensional heavy fermions on the strongly correlated boundaries of Kondo topological insulators
• Model Hamiltonian for topological Kondo insulator SmB6
• Optical conductivity of an interacting Weyl liquid in the collisionless regime
• Particle-Hole Asymmetry in Gapped Topological Insulator Surface States
• Ferromagnetism and glassiness on the surface of topological insulators
• Two relativistic Kondo effects: Classification with particle and antiparticle impurities
• Magnetization of the Metallic Surface States in Topological Insulators
• Shadow surface states in topological Kondo insulators
• Quantized thermal and spin transports of dirty planar topological superconductors
• Valence transition in topological Kondo insulator