Topological surface states in the Kondo insulator YbB${}_{12}$ revealed via planar tunneling spectroscopy

Abstract

Planar tunneling spectroscopy of the Kondo insulator SmB${}_6$ suggests that an interaction between the surface Dirac fermions and the bulk spin excitons results in incompletely protected topological surface states. To gain further insight into their true nature, it is necessary to study other topological Kondo insulator candidates. Calculations of electronic energy bands predict that the Kondo insulator YbB${}_{12}$ hosts topological surface states protected by crystalline mirror symmetry. In this study, we present tunneling conductance spectra obtained from the (001) surface of YbB${}_{12}$ single crystals and discuss them in comparison to SmB${}_6$. The linear conductance at low bias provides strong evidence for the existence of surface Dirac fermions. The double-hump structure in the negative bias region is associated with hybridized band edges, in agreement with a calculated band structure. While these similarities with SmB6 are suggestive of the existence of topological surface states in YbB${}_{12}$, in agreement with other experiments, some discrepancies are also observed, which we attribute to a difference in their exact nature from those in SmB${}_6$.

arXiv comment25 pages, 7 figures, submitted to Physical Review B

References in corpus (49)

• Topological Insulators
• Topological insulators and superconductors
• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Topological Insulators in Three Dimensions
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Topological Crystalline Insulators
• Topological Crystalline Insulators in the SnTe Material Class
• Topological Kondo Insulators
• Three-Dimensional Topological Insulators
• Surface electronic structure of the topological Kondo insulator candidate correlated electron system SmB6
• Correlated Topological Insulators with Mixed Valence
• Topological surface state in the Kondo Insulator Samarium Hexaboride
• 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
• Helical edge and surface states in HgTe quantum wells and bulk insulators
• Cubic Topological Kondo Insulators
• Topological Crystalline Kondo Insulator in Mixed Valence Ytterbium Borides
• Hybridization, Inter-Ion Correlation, and Surface States in the Kondo Insulator SmB6
• Tuning bulk and surface conduction in topological Kondo insulator SmB6
• Hybridization gap and Fano resonance in SmB${}_6$
• Quantum Oscillations of Electrical Resistivity in an Insulator
• Emergence of a coherent in-gap state in SmB6 Kondo insulator revealed by scanning tunneling spectroscopy
• Momentum-Dependent Hybridization Gap and dispersive in-gap state of The Kondo Semiconductor SmB6
• Interaction Driven Subgap Spin Exciton in the Kondo Insulator SmB6
• Samarium hexaboride: A trivial surface conductor
• Kondo hybridisation and the origin of metallic states at the (001) surface of SmB6
• The importance of Charge Fluctuations for the Topological Phase in SmB${}_6$
• Evidence for short-range antiferromagnetic fluctuations in Kondo-insulating YbB12
• Surface Kondo Effect and Non-Trivial Metallic State of the Kondo Insulator YbB12
• Fermi surfaces in Kondo insulators
• Quantum oscillations in flux-grown SmB6 with embedded aluminum
• Unconventional thermal metallic state of charge-neutral fermions in an insulator
• Topological surface states interacting with bulk excitations in the Kondo insulator SmB${}_6$ revealed via planar tunneling spectroscopy
• Indirect and direct energy gaps in the Kondo semiconductor YbB12
• Unusual high-field metal in a Kondo insulator
• Hybridization gap formation in the Kondo insulator YbB${}_{12}$ observed using time-resolved photoemission spectroscopy
• Incomplete Protection of the Surface Weyl Cones of the Kondo Insulator SmB${}_6$: Spin Exciton Scattering
• Topological surface conduction in Kondo insulator YbB${}_{12}$
• $f$-electron hybridised metallic Fermi surface in magnetic field-induced metallic YbB${}_{12}$
• Definitive Surface Magnetotransport Study of SmB${}_6$
• The Effects of Spin-Excitons on the Surface States of SmB6: A Photoemission Study
• Hall anomaly, Quantum Oscillations and Possible Lifshitz Transitions in Kondo Insulator YbB${}_{12}$: Evidence for Unconventional Charge Transport
• Bulk Rotational Symmetry Breaking in Kondo Insulator SmB6
• Electrical detection of surface spin polarization of candidate topological Kondo insulator SmB6
• Planar tunneling spectroscopy of the topological Kondo insulator SmB${}_6$
• Topological nature of the Kondo insulator SmB${}_6$ and its sensitiveness to Sm vacancy

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