Samarium hexaboride: A trivial surface conductor

Abstract

Recent theoretical and experimental studies suggest that SmB${}_6$ is the first topological Kondo insulator: A material in which the interaction between localized and itinerant electrons renders the bulk insulating at low temperature, while topological surface states leave the surface metallic. While this would elegantly explain the material's puzzling conductivity, we find the experimentally observed candidates for both predicted topological surface states to be of trivial character instead: The surface state at $\bar{\Gamma }$ is very heavy and shallow with a mere $\sim 2$ meV binding energy. It exhibits large Rashba splitting which excludes a topological nature. We further demonstrate that the other metallic surface state, located at $\bar{X}$, is not an independent in-gap state as supposed previously, but part of a massive band with much higher binding energy (1.7 eV). We show that it remains metallic down to 1 K due to reduced hybridization with the energy-shifted surface 4$f$ level.

10 pages, 4 figures

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Cited by in corpus (43)

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• Imaging emergent heavy Dirac fermions of a topological Kondo insulator
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• Spin-valley locking, bulk quantum Hall effect and chiral surface state in a noncentrosymmetric Dirac semimetal BaMnSb${}_2$
• Quantum oscillations in flux-grown SmB6 with embedded aluminum
• Magnetic and defect probes of the SmB${}_6$ surface state
• Spin- and angle-resolved photoemission on topological materials
• Non-trivial surface states of samarium hexaboride at the (111) surface
• Consistency between ARPES and STM measurements on SmB${}_6$
• Observation of a well-defined hybridization gap and in-gap states on the SmB6 (001) surface
• Metallic surface states in a correlated d-electron topological Kondo insulator candidate FeSb2
• Chemical and valence reconstruction at the surface of SmB6 revealed with resonant soft x-ray reflectometry
• 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
• Surface-induced positive planar Hall effect in topological Kondo insulator SmB6 microribbons
• Probing FeSi, a d-electron topological Kondo insulator candidate, with magnetic field, pressure, and microwaves
• Diamagnetic Sm${}^{3+}$ in the topological Kondo insulator SmB${}_6$
• Intrinsic Low-Temperature Magnetism in SmB6
• Topology of SmB${}_6$ determined by dynamical mean field theory
• A RIXS investigation of the crystal-field splitting of Sm${}^{3+}$ in SmB${}_6$
• Multiple topological Dirac cones in a mixed-valent Kondo semimetal: g-SmS
• Bulk transport paths through defects in floating zone and Al flux grown SmB${}_6$
• Spin-selective tunneling from nanowires of the candidate topological Kondo insulator SmB6
• Robust surface states and coherence phenomena in magnetically alloyed SmB6
• Non-universal weak antilocalization effect in cubic topological Kondo insulators
• Breakdown of bulk-projected isotropy in surface electronic states of topological Kondo insulator SmB${}_6$(001)
• Comparative Scanning Tunneling Microscopy Study on Hexaborides
• An STM perspective on hexaborides: Surface states of the Kondo insulator SmB${}_6$
• Topological surface states in the Kondo insulator YbB${}_{12}$ revealed via planar tunneling spectroscopy
• Slow crystalline electric field fluctuations in the Kondo lattice SmB${}_6$
• Universal Signatures of Majorana-like Quasiparticles in Strongly Correlated Landau-Fermi Liquids
• Topology of SmB6 revisited by means of topological quantum chemistry
• Phase stability in SmB${}_6$
• Anomalously large spin-current voltages on the surface of SmB${}_6$
• Mixed-valence state in the dilute-impurity regime of La-substituted SmB${}_6$
• Surface excitations relaxation in the Kondo insulator Sm${}_{1-x}$Gd${}_x$B${}_6$
• 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
• Report on reproducibility in condensed matter physics
• Fragility of Topology under Electronic Correlations in Iron Chalcogenides
• Spectral properties of strongly correlated multi impurity models in the Kondo insulator regime: Emergent coherence, metallic surface states and quantum phase transitions
• Anisotropic Surface State Band Splitting and Low Energy Flat Bands in 3d Correlated Topological Kondo Insulator Candidate FeSb${}_2$