A new exotic state in an old material: A tale of Samarium Hexaboride

Abstract

We review current theoretical and experimental efforts to identify a novel class of intermetallic 4f and 5f orbital materials in which strong interactions between itinerant and predominately localized degrees of freedom gives rise to a bulk insulating state at low temperatures, while the surface remains metallic. This effect arises due to inversion of even parity conduction bands and odd parity very narrow f-electron bands. The number of band inversions is mainly determined by the crystal symmetry of a material and the corresponding degeneracy of the hybridized f-electron bands. For odd number of band inversions the metallic surface states are chiral and therefore remain robust against disorder and time-reversal invariant perturbations. We discuss a number of unresolved theoretical issues specific to topological Kondo insulators and outline experimental challenges in probing the chiral surface states in these materials.

Invited contribution to the JETP issue dedicated to the 80th anniversary of Professor Anatoly I. Larkin

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Cited by in corpus (18)

• Colloquium: Topological Band Theory
• Fractionalized Topological Insulators
• Fractional Topological Insulators -- a Pedagogical Review
• Topological invariants, surface states, and interaction-driven phase transitions in correlated Kondo insulators with cubic symmetry
• 4$f$ crystal field ground state of the strongly correlated topological insulator SmB${}_6$
• CeRu${}_4$Sn${}_6$: a strongly correlated material with nontrivial topology
• Surface-state spin textures and mirror Chern numbers in topological Kondo insulators
• Bulk and surface electronic properties of SmB6: a hard x-ray photoelectron spectroscopy study
• In-gap collective mode spectrum of the Topological Kondo Insulator SmB6
• Model Hamiltonian for topological Kondo insulator SmB6
• Magnetic impurities in Kondo insulators: An application to samarium hexaboride
• Topological Phases in Oxide Heterostructures with Light and Heavy Transition Metal Ions
• A RIXS investigation of the crystal-field splitting of Sm${}^{3+}$ in SmB${}_6$
• Kramers' doublet ground state in topological Kondo insulators
• Pseudo-Spin, Real-Spin and Spin Polarization of Photo-emitted Electrons
• Ce 3$p$ hard x-ray photoelectron spectroscopy study of the topological Kondo insulator CeRu${}_4$Sn${}_6$
• Valence transition in topological Kondo insulator
• f-electron charge densities probed using core level non-resonant inelastic x-ray scattering