Additional energy scale in SmB${}_6$ at low temperature

Abstract

Topological insulators give rise to exquisite electronic properties due to their spin-momentum locked Dirac-cone-like band structure. Recently, it has been suggested that the required opposite parities between valence and conduction band along with strong spin-orbit coupling can be realized in correlated materials. Particularly, SmB${}_6$ has been proposed as candidate material for a topological Kondo insulator. By utilizing scanning tunneling microscopy and spectroscopy measurements down to 0.35 K, we observed several states within the hybridization gap of about $\pm$20 meV on well characterized (001) surfaces of SmB${}_6$. The spectroscopic response to impurities and magnetic fields allows to distinguish between dominating bulk and surface contributions to these states. The surface contributions develop particularly strongly below about 7 K which can be understood in terms of a breakdown of the Kondo effect at the surface. Our high-resolution data provide detailed insight into the electronic structure of SmB${}_6$, which will reconcile many current discrepancies on this compound.

References in corpus (40)

• Topological Kondo Insulators
• Surface electronic structure of the topological Kondo insulator candidate correlated electron system SmB6
• Low-temperature surface conduction in the Kondo insulator SmB${}_6$
• Correlated Topological Insulators with Mixed Valence
• Topological surface state in the Kondo Insulator Samarium Hexaboride
• Quantum oscillations in Kondo Insulator SmB${}_6$
• Robust Surface Hall Effect and Nonlocal Transport in SmB6: Indication for an Ideal Topological Insulator
• 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
• Cubic Topological Kondo Insulators
• Hybridization, Inter-Ion Correlation, and Surface States in the Kondo Insulator SmB6
• Polarity-driven surface metallicity in SmB${}_6$
• Hybridization gap and Fano resonance in SmB${}_6$
• Electron Cotunneling into a Kondo Lattice
• 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
• Differential Conductance and Quantum Interference in Kondo Systems
• One-dimensional edge state transport in a topological Kondo insulator
• Samarium hexaboride: A trivial surface conductor
• The importance of Charge Fluctuations for the Topological Phase in SmB${}_6$
• The energy gap of intermediate-valent SmB6 studied by point-contact spectroscopy
• Exotic Kondo crossover in a wide temperature region in the topological Kondo insulator SmB6 revealed by high-resolution ARPES
• Termination-dependent Surface In-gap States in a Mixed-valent Topological Insulator: SmB${}_6$
• SmB6 Photoemission: Past and Present
• Heavy surface state in a possible topological Kondo insulator: Magneto-thermoelectric transport on the (011)-plane of SmB${}_6$
• Coexistence of light and heavy surface states in a topological multi-band Kondo insulator
• Band symmetries of mixed-valence topological insulator: SmB6
• Electronic structure of YbB${}_6$: Is it a Topological Insulator or not?
• Scanning tunneling spectroscopy and surface quasiparticle interference in models for the strongly correlated topological insulators SmB6 and PuB6
• Temperature Dependence of Linked Gap and Surface State Evolution in the Mixed Valent Topological Insulator SmB6
• Surface and electronic structure of SmB${}_6$ through Scanning Tunneling Microscopy
• Comparative study of rare earth hexaborides using high resolution angle-resolved photoemission
• Spin- and angle-resolved photoemission on the topological Kondo Insulator candidate: SmB6
• Quantum phase transition and destruction of Kondo effect in pressurized SmB6
• Magnetoresistance evidence on surface state and field-dependent bulk gap in Kondo insulator SmB6
• Robust local and non-local transport in the Topological Kondo Insulator SmB${}_6$ in the presence of high magnetic field

Cited by in corpus (31)

• Microscopic evidence for a chiral superconducting order parameter in the heavy fermion superconductor UTe2
• Imaging emergent heavy Dirac fermions of a topological Kondo insulator
• 4$f$ crystal field ground state of the strongly correlated topological insulator SmB${}_6$
• Magnetic and defect probes of the SmB${}_6$ surface state
• Bulk and surface electronic properties of SmB6: a hard x-ray photoelectron spectroscopy study
• Consistency between ARPES and STM measurements on SmB${}_6$
• Coexistence of Quasi-two-dimensional Superconductivity and Tunable Kondo Lattice in a van der Waals Superconductor
• Observation of a well-defined hybridization gap and in-gap states on the SmB6 (001) surface
• Kondo-induced giant isotropic negative thermal expansion
• Chemical and valence reconstruction at the surface of SmB6 revealed with resonant soft x-ray reflectometry
• 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
• Kondo interaction in FeTe and its potential role in the magnetic order
• Bulk Rotational Symmetry Breaking in Kondo Insulator SmB6
• Large positive correlation between the effective electron mass and the multipolar fluctuation in the heavy-fermion metal Ce${}_{1-x}$La${}_x$B${}_6$
• Multiple topological Dirac cones in a mixed-valent Kondo semimetal: g-SmS
• A RIXS investigation of the crystal-field splitting of Sm${}^{3+}$ in SmB${}_6$
• Ultrafast terahertz spectroscopy study of Kondo insulating thin film SmB${}_6$: evidence for an emergent surface state
• Spin-selective tunneling from nanowires of the candidate topological Kondo insulator SmB6
• Cross-over behavior of the localized to itinerant transition of 5f electrons in the antiferromagnetic Kondo lattice USb2
• Comparative Scanning Tunneling Microscopy Study on Hexaborides
• An STM perspective on hexaborides: Surface states of the Kondo insulator SmB${}_6$
• Unconventional Josephson junctions with topological Kondo insulator weak links
• Phase stability in SmB${}_6$
• A Mean-Field Study of Quantum Oscillations in Two-Dimensional Kondo Insulators
• Surface excitations relaxation in the Kondo insulator Sm${}_{1-x}$Gd${}_x$B${}_6$
• Persistence of correlation-driven surface states in SmB6 under pressure
• f-electron charge densities probed using core level non-resonant inelastic x-ray scattering
• Distinct effect of Kondo physics on crystal field splitting in electron and spin spectroscopies
• Anomalous 4$f$ fine structure in TmSe${}_{1-x}$Te${}_x$ across the metal-insulator transition
• 3D Topological Kondo Insulators