Non-trivial surface states of samarium hexaboride at the (111) surface

Abstract

The peculiar metallic electronic states observed in the Kondo insulator, samarium hexaboride (SmB${}_6$), has stimulated considerable attention among those studying non-trivial electronic phenomena. However, experimental studies of these states have led to controversial conclusions mainly to the difficulty and inhomogeneity of the SmB${}_6$ crystal surface. Here, we show the detailed electronic structure of SmB${}_6$ with angle-resolved photoelectron spectroscopy measurements of the three-fold (111) surface where only two inequivalent time-reversal-invariant momenta (TRIM) exist. We observe the metallic two-dimensional state was dispersed across the bulk Kondo gap. Its helical in-plane spin polarisation around the surface TRIM suggests that SmB${}_6$ is topologically non-trivial, according to the topological classification theory for weakly correlated systems. Based on these results, we propose a simple picture of the controversial topological classification of SmB${}_6$.

arXiv comment34 pages, 4 figures for main text; 9 figures for supplementary material

References in corpus (25)

• Topological Insulators
• Mott physics and band topology in materials with strong spin-orbit interaction
• Topological Kondo Insulators
• Surface States of the Topological Insulator Bi_{1-x}Sb_x
• Surface electronic structure of the topological Kondo insulator candidate correlated electron system SmB6
• Quantum oscillations in Kondo Insulator SmB${}_6$
• Observation of in-gap surface states in the Kondo insulator SmB6 by photoemission
• Unconventional Fermi surface in an insulating state
• Direct observation of the spin texture in strongly correlated SmB6 as evidence of the topological Kondo insulator
• Surface and Bulk Electronic Structure of the Strongly Correlated System SmB${}_6$ and Implications for a Topological Kondo Insulator
• Direct Measurement of the Out-of-Plane Spin Texture in the Dirac Cone Surface State of a Topological Insulator
• Hybridization gap and Fano resonance in SmB${}_6$
• Fermi surface in the absence of a Fermi liquid in the Kondo insulator SmB${}_6$
• Kondo Breakdown in Topological Kondo Insulators
• Momentum-Dependent Hybridization Gap and dispersive in-gap state of The Kondo Semiconductor SmB6
• Correlation between bulk thermodynamic measurements and the low temperature resistance plateau in SmB6
• Samarium hexaboride: A trivial surface conductor
• Surface Kondo Effect and Non-Trivial Metallic State of the Kondo Insulator YbB12
• The energy gap of intermediate-valent SmB6 studied by point-contact spectroscopy
• Coexistence of light and heavy surface states in a topological multi-band Kondo insulator
• Spin-polarized angle-resolved photoelectron spectroscopy of the so-predicted Kondo topological insulator SmB6
• Incomplete Protection of the Surface Weyl Cones of the Kondo Insulator SmB${}_6$: Spin Exciton Scattering
• Bulk Rotational Symmetry Breaking in Kondo Insulator SmB6
• Spin textures on general surfaces of the correlated topological insulator SmB6
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• Consistency between ARPES and STM measurements on SmB${}_6$
• Definitive Surface Magnetotransport Study of SmB${}_6$
• Hall anomaly, Quantum Oscillations and Possible Lifshitz Transitions in Kondo Insulator YbB${}_{12}$: Evidence for Unconventional Charge Transport
• Topology of SmB${}_6$ determined by dynamical mean field theory
• A RIXS investigation of the crystal-field splitting of Sm${}^{3+}$ in SmB${}_6$
• Robust surface states and coherence phenomena in magnetically alloyed SmB6
• Breakdown of bulk-projected isotropy in surface electronic states of topological Kondo insulator SmB${}_6$(001)
• Topology of SmB6 revisited by means of topological quantum chemistry
• Bulk-Sensitive Spin-Resolved Resonant Electron Energy-Loss Spectroscopy (SR-rEELS): Observation of Element- and Spin-Selective Bulk Plasmons
• Persistence of correlation-driven surface states in SmB6 under pressure
• Observation of the superconducting proximity effect from surface states in SmB${}_6$/YB${}_6$ thin film heterostructures via terahertz spectroscopy
• Mapping out the emergence of topological features in the highly alloyed topological Kondo insulators Sm${}_{1-x}{M}_x$B${}_6$ ($M$=Eu, Ce)
• Valence transition in topological Kondo insulator
• Anisotropic Surface State Band Splitting and Low Energy Flat Bands in 3d Correlated Topological Kondo Insulator Candidate FeSb${}_2$