Observation of in-gap surface states in the Kondo insulator SmB6 by photoemission

Abstract

Kondo insulators (KIs) are strongly correlated materials in which the interactions between 4f and conduction electrons lead to a hybridization gap opening at low temperature 1-2. SmB6 is a typical KI, but its resistivity does not diverge at low temperatures, which was attributed to some in-gap states 3-10. However after several decades of research, the nature and origin of the in-gap states remain unclear. Recent band calculation and transport measurements suggest that the in-gap states could actually be ascribed to topological surface states. SmB6 thus might be the first realization of topological Kondo insulator (TKI) 13, the strongly correlated version of topological insulator (TI) 11,12. Here by performing angle-resolved photoemission spectroscopy (ARPES), we directly observed several dispersive states within the hybridization gap of SmB6, which cross the Fermi level and show negligible kz dependence, indicative of their surface origin. Furthermore, the circular dichroism (CD) ARPES results of the in-gap states suggest the chirality of orbital momentum, and temperature dependent measurements have shown that the in-gap states vanish simultaneously with the hybridization gap around 150 K. These strongly suggest their possible topological origin.

18 pages, 8 figures

References in corpus (4)

• Surface electronic structure of the topological Kondo insulator candidate correlated electron system SmB6
• Correlated Topological Insulators with Mixed Valence
• Surface and Bulk Electronic Structure of the Strongly Correlated System SmB${}_6$ and Implications for a Topological Kondo Insulator
• Hybridization, Inter-Ion Correlation, and Surface States in the Kondo Insulator SmB6

Cited by in corpus (180)

• Colloquium: Topological Band Theory
• Electronic structure of quantum materials studied by angle-resolved photoemission spectroscopy
• Interacting topological insulators: a review
• Surface electronic structure of the topological Kondo insulator candidate correlated electron system SmB6
• Quantum oscillations in Kondo Insulator SmB${}_6$
• Topological Kondo Insulators
• Signature of strong spin-orbital coupling in the large non-saturating magnetoresistance material WTe2
• New classes of topological crystalline insulators with unpinned surface Dirac cones
• Direct observation of the spin texture in strongly correlated SmB6 as evidence of the topological Kondo insulator
• Quantum Materials for Spin and Charge Conversion
• Using Gap Symmetry and Structure to Reveal the Pairing Mechanism in Fe-based Superconductors
• Tuning bulk and surface conduction in topological Kondo insulator SmB6
• Hybridization gap and Fano resonance in SmB${}_6$
• Kondo Breakdown in Topological Kondo Insulators
• Kondo Breakdown and Quantum Oscillations in SmB${}_6$
• Emergence of a coherent in-gap state in SmB6 Kondo insulator revealed by scanning tunneling spectroscopy
• Interaction Driven Subgap Spin Exciton in the Kondo Insulator SmB6
• One-dimensional edge state transport in a topological Kondo insulator
• Correlation between bulk thermodynamic measurements and the low temperature resistance plateau in SmB6
• Skyrme insulators: insulators at the brink of superconductivity
• Möbius Kondo Insulators
• Emergence of supersymmetric quantum electrodynamics
• Additional energy scale in SmB${}_6$ at low temperature
• The importance of Charge Fluctuations for the Topological Phase in SmB${}_6$
• Imaging emergent heavy Dirac fermions of a topological Kondo insulator
• Bona fide interaction-driven topological phase transition in correlated SPT states
• Surface Kondo Effect and Non-Trivial Metallic State of the Kondo Insulator YbB12
• Topological invariants, surface states, and interaction-driven phase transitions in correlated Kondo insulators with cubic symmetry
• Weak Antilocalization and Linear Magnetoresistance in The Surface State of SmB6
• Surface Theory of a Family of Topological Kondo Insulators
• Observation of perfect Andreev reflection due to Klein paradox in a topological superconducting state
• Anomalous 3D bulk AC conduction within the Kondo gap of SmB${}_6$ single crystals
• Non-Kondo-like Electronic Structure in the Correlated Rare-Earth Hexaboride YbB${}_6$
• Exotic Kondo crossover in a wide temperature region in the topological Kondo insulator SmB6 revealed by high-resolution ARPES
• Large, high quality single-crystals of the new Topological Kondo Insulator, SmB6
• Exceptional band touching for strongly correlated systems in equilibrium
• Quantum oscillations in flux-grown SmB6 with embedded aluminum
• Topological surface states interacting with bulk excitations in the Kondo insulator SmB${}_6$ revealed via planar tunneling spectroscopy
• SmB6 Photoemission: Past and Present
• 4$f$ crystal field ground state of the strongly correlated topological insulator SmB${}_6$
• Tunable Electronic Structure and Surface States in Rare Earth Mono-Bismuthides with Partially Filled f Shell
• Composition-spread Growth and the Robust Topological Surface State of Kondo insulator SmB6 Thin Films
• Hysteretic Magnetotransport in SmB6 at Low Magnetic Fields
• Fermi Surface Topology and Hotspots Distribution in Kondo Lattice System CeB6
• Coexistence of light and heavy surface states in a topological multi-band Kondo insulator
• Magnetotransport Measurements of the Surface States of Samarium Hexaboride using Corbino Structures
• CeRu${}_4$Sn${}_6$: a strongly correlated material with nontrivial topology
• Spin Injection and Inverse Edelstein Effect in the Surface States of Topological Kondo Insulator SmB6
• Heavy Weyl fermion state in CeRu${}_4$Sn${}_6$
• Surface-state spin textures and mirror Chern numbers in topological Kondo insulators
• Breakdown of the Kondo insulating state in SmB6 by introducing Sm vacancies
• Unconventional transformation of spin Dirac phase across a topological quantum phase transition
• Pressure-resistant intermediate valence in Kondo insulator SmB6
• Bulk Fermi surface of charge-neutral excitations in SmB6 or not: a heat-transport study
• Angle-resolved Photoemission Spectroscopy Study on the Surface States of the Correlated Topological Insulator YbB6
• End states in a 1-D topological Kondo insulator
• Bulk and surface electronic properties of SmB6: a hard x-ray photoelectron spectroscopy study
• Surface state reconstruction in ion-damaged SmB_6
• Pressure-induced quantum phase transitions in topological insulator YbB6
• Scanning tunneling spectroscopy and surface quasiparticle interference in models for the strongly correlated topological insulators SmB6 and PuB6
• Topological invariants for interacting topological insulators: II. Breakdown of the Green's function formalism
• Spin-polarized angle-resolved photoelectron spectroscopy of the so-predicted Kondo topological insulator SmB6
• Possible devil's staircase in the Kondo lattice CeSbSe
• Low-temperature magnetic fluctuations in the Kondo insulator SmB6
• Distinct topological crystalline phases in models for the strongly correlated topological insulator SmB6
• Racah materials: role of atomic multiplets in intermediate valence systems
• Temperature Dependence of Linked Gap and Surface State Evolution in the Mixed Valent Topological Insulator SmB6
• Consistency between ARPES and STM measurements on SmB${}_6$
• Non-trivial surface states of samarium hexaboride at the (111) surface
• Towards the manipulation of topological states of matter: A perspective from electron transport
• Hybridization gap formation in the Kondo insulator YbB${}_{12}$ observed using time-resolved photoemission spectroscopy
• Magnetic field-tuned quantum criticality in a Kondo insulator
• In-gap collective mode spectrum of the Topological Kondo Insulator SmB6
• Incomplete Protection of the Surface Weyl Cones of the Kondo Insulator SmB${}_6$: Spin Exciton Scattering
• Two distinct topological phases in the mixed valence compound YbB6 and its differences from SmB6
• Two-dimensional heavy fermions on the strongly correlated boundaries of Kondo topological insulators
• Observation of the superconducting proximity effect in the surface state of SmB6 thin films
• Visualizing the atomic-scale origin of metallic behavior in Kondo insulators
• Parity-violating hybridization in heavy Weyl semimetals
• Magnetic states in a three-dimensional topological Kondo insulator
• Excitonic and Nematic Instabilities on the Surface of Topological Kondo Insulators
• Comparative study of rare earth hexaborides using high resolution angle-resolved photoemission
• Chemical and valence reconstruction at the surface of SmB6 revealed with resonant soft x-ray reflectometry
• Topological phase in $1D$ topological Kondo insulator: $Z_2$ topological insulator, Haldane-like phase and Kondo breakdown
• Metallic surface states in a correlated d-electron topological Kondo insulator candidate FeSb2
• Model Hamiltonian for topological Kondo insulator SmB6
• Fractionalized Fermi liquid on the surface of a topological Kondo insulator
• A Strongly-Interacting Dirac Liquid on the Surface of a Topological Kondo Insulator
• Observation of metallic surface states in the strongly correlated Kitaev-Heisenberg candidate Na2IrO3
• Suppression of magnetic excitations near the surface of the topological Kondo insulator SmB6
• Valence Characterization of Surface and Subsurface Region in SmB6
• Definitive Surface Magnetotransport Study of SmB${}_6$
• Critical role of magnetic moments in heavy-fermion materials: revisiting mysteries of SmB${}_6$
• Hall anomaly, Quantum Oscillations and Possible Lifshitz Transitions in Kondo Insulator YbB${}_{12}$: Evidence for Unconventional Charge Transport
• Suppression of dense Kondo state in CeB6 under pressure
• Crossover of Magnetoresistance from Fourfold to Twofold Symmetry in SmB6 Single Crystal, a topological Kondo insulator
• Surface-induced positive planar Hall effect in topological Kondo insulator SmB6 microribbons
• The Effects of Spin-Excitons on the Surface States of SmB6: A Photoemission Study
• Imaging the Kondo Insulating Gap on SmB6
• Spin textures on general surfaces of the correlated topological insulator SmB6
• Magnetic impurities in Kondo insulators: An application to samarium hexaboride
• Diamagnetic Sm${}^{3+}$ in the topological Kondo insulator SmB${}_6$
• Robust Surface States indicated by Magnetotransport in SmB6 Thin Films
• ARPES insights on the metallic states of YbB6(001): E(k) dispersion, temporal changes and spatial variation
• Spin- and angle-resolved photoemission on the topological Kondo Insulator candidate: SmB6
• Electrical detection of surface spin polarization of candidate topological Kondo insulator SmB6
• The anomalous antiferromagnetic topological phase in pressurized SmB6
• Anomalous Hall Effect on the surface of topological Kondo insulators
• Metallic Surface States Probed Within the Microwave Skin Depth of the Putative Topological Insulator YBiPt Compound
• Chern Kondo Insulator in an Optical Lattice
• Behavior of gapped and ungapped Dirac cones in an antiferromagnetic topological metal, SmBi
• Surface properties of SmB6 from x-ray photoelectron spectroscopy
• Planar tunneling spectroscopy of the topological Kondo insulator SmB${}_6$
• Topology of SmB${}_6$ determined by dynamical mean field theory
• Multiple topological Dirac cones in a mixed-valent Kondo semimetal: g-SmS
• Interference Evidence for Rashba-Type Spin-Split on Semimetallic WTe2 Surface
• A RIXS investigation of the crystal-field splitting of Sm${}^{3+}$ in SmB${}_6$
• Reduction of the low-temperature bulk gap in samarium hexaboride under high magnetic fields
• Understanding low-temperature bulk transport in samarium hexaboride without relying on in-gap bulk states
• Signature of surface state coupling in thin films of the topological Kondo insulator SmB${}_6$ from anisotropic magnetoresistance
• ${}^{239}$Pu nuclear magnetic resonance in the candidate topological insulator PuB${}_4$
• Uncovering the behavior of Hf2Te2P and the candidate Dirac metal Zr2Te2P
• Ferromagnetism and glassiness on the surface of topological insulators
• Magnetoresistance and Kondo effect in the nodal-line semimetal VAs${}_2$
• Many-body instabilities and mass generation in slow Dirac materials
• Ultrafast terahertz spectroscopy study of Kondo insulating thin film SmB${}_6$: evidence for an emergent surface state
• Impurities or a neutral Fermi surface? A further examination of the low-energy ac optical conductivity of SmB${}_6$
• Topological Charge/spin density Wave in InAs/GaSb Quantum Wells under an In-plane Magnetic Field
• Bulk transport paths through defects in floating zone and Al flux grown SmB${}_6$
• Robust surface states and coherence phenomena in magnetically alloyed SmB6
• Dirac-Kondo semimetals and topological Kondo insulators in the dilute carrier limit
• Shadow surface states in topological Kondo insulators
• Universal properties of the near-gap spectra of SmB6: dynamical mean-field calculations and photoemission experiments
• Restoration of topological properties at finite temperatures in a heavy-fermion system
• Finite temperature physics of $1D$ topological Kondo insulator: Stable Haldane phase, Emergent energy scale and Beyond
• Itinerant to relocalized transition of f electrons in the Kondo insulator CeRu4Sn6
• Distinct Kondo Screening Behaviors in Heavy Fermion Filled Skutterudites with 4f1 and 4f2 Configurations
• Surface vs bulk electronic structures of a moderately correlated topological insulator YbB6 revealed by ARPES
• How to identify and characterize strongly correlated topological semimetals
• Probing the interplay between surface and bulk states in the topological Kondo insulator SmB${}_6$ through conductance fluctuation spectroscopy
• Irreversible proliferation of magnetic moments at cleaved surfaces of the topological Kondo insulator SmB6
• Many-body breakdown of indirect gap in topological Kondo insulators
• Breakdown of bulk-projected isotropy in surface electronic states of topological Kondo insulator SmB${}_6$(001)
• Topological nature of the Kondo insulator SmB${}_6$ and its sensitiveness to Sm vacancy
• Pseudo-Spin, Real-Spin and Spin Polarization of Photo-emitted Electrons
• An STM perspective on hexaborides: Surface states of the Kondo insulator SmB${}_6$
• Frustration-induced quantum criticality in Ni-doped CePdAl as revealed by the $\mu$SR technique
• Electrical detection of the inverse Edelstein effect on the surface of SmB${}_6$
• Hard and soft x-ray photoemission spectroscopy study of the new Kondo system SmO thin film
• Pressure-Driven Topological Phase Transition in the Yb Chalcogenides YbO and YbS
• Magnetism of an adatom on biased AA-stacked bilayer graphene
• Microwave Meissner Screening of Proximity coupled Topological Insulator / Superconductor Bilayers
• Surface reconstruction in a tight-binding model for the topological Kondo insulator SmB6
• Quantum phase transition and destruction of Kondo effect in pressurized SmB6
• Tunable Kondo resonance at a pristine two-dimensional Dirac semimetal on a Kondo insulator
• Interacting topological phases in thin films of topological mirror Kondo insulators
• Topological surface states in the Kondo insulator YbB${}_{12}$ revealed via planar tunneling spectroscopy
• Floquet states in (LaNiO${}_3$)${}_2$/(LaAlO${}_3$)${}_N$ heterostructures grown along the (111) direction
• Inexorable Edge Kondo Breakdown in Topological Kondo Insulators
• Emergence of electronic modes by doping Kondo insulators in the Kondo lattice and periodic Anderson models
• Hall coefficient diagnostics of surface state in pressurized SmB6
• Spontaneous symmetry breaking and quantum Hall valley ordering on the surface of topological hexaborides
• Topology of SmB6 revisited by means of topological quantum chemistry
• Magnetic effects on Chern Kondo insulator
• 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
• Mapping out the emergence of topological features in the highly alloyed topological Kondo insulators Sm${}_{1-x}{M}_x$B${}_6$ ($M$=Eu, Ce)
• f-electron charge densities probed using core level non-resonant inelastic x-ray scattering
• Large ferromagnetic-like band splitting in ultrathin ${\mathrm{SmC}}_6$ films
• Fragility of Topology under Electronic Correlations in Iron Chalcogenides
• Emergent photovoltage on SmB6 surface upon bulk-gap evolution revealed by pump-and-probe photoemission spectroscopy
• Nanoscale Conducting and Insulating Domains on YbB${}_6$
• Nesting-driven antiferromagnetic order in Kondo lattice CePd5Al2
• Direct measurement of a remnant Fermi surface in SmB6
• Electronic correlations and topology in Kondo insulator PuB${}_6$
• Intrinsic one-dimensional conducting channels in the Kondo insulator SmB6
• Effect of valence fluctuations on the ground state properties of SmB6
• Fate of a multiple-band Fermi liquid that is coupled with critical ${\varphi }^4$ bosons