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 (12)

• Correlated Topological Insulators with Mixed Valence
• Direct observation of the spin texture in strongly correlated SmB6 as evidence of the topological Kondo insulator
• Hybridization, Inter-Ion Correlation, and Surface States in the Kondo Insulator SmB6
• Electron Cotunneling into a Kondo Lattice
• Kondo Breakdown in Topological Kondo Insulators
• Interaction Driven Subgap Spin Exciton in the Kondo Insulator SmB6
• 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${}_6$
• Heavy surface state in a possible topological Kondo insulator: Magneto-thermoelectric transport on the (011)-plane of SmB${}_6$
• Scanning tunneling spectroscopy and surface quasiparticle interference in models for the strongly correlated topological insulators SmB6 and PuB6
• Spin- and angle-resolved photoemission on the topological Kondo Insulator candidate: 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 (10)

• 4$f$ crystal field ground state of the strongly correlated topological insulator SmB${}_6$
• 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${}_6$
• Spin-selective tunneling from nanowires of the candidate topological Kondo insulator SmB6
• An STM perspective on hexaborides: Surface states of the Kondo insulator SmB${}_6$
• Phase stability in 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
• f-electron charge densities probed using core level non-resonant inelastic x-ray scattering
• 3D Topological Kondo Insulators