Composition-spread Growth and the Robust Topological Surface State of Kondo insulator SmB6 Thin Films

Abstract

Topological insulators are a class of materials with insulating bulk but protected conducting surfaces due to the combination of spin-orbit interactions and time-reversal symmetry. The surface states are topologically non-trivial and robust against non-magnetic backscattering, leading to interesting physics and potential quantum computing applications1, 2. Recently there has been a fast growing interest in samarium hexboride (SmB6), a Kondo insulator predicted to be the first example of a correlated topological insulator3, 4. Here we fabricated smooth thin films of nanocrystalline SmB6 films. Their transport behavior indeed shows that SmB6 is a bulk insulator with topological surface states. Upon decreasing the temperature, the resistivity \r{ho} of Sm0.14B0.86 (SmB6) films display significant increase below 50 K due to hybridization gap formation, and it shows a saturation behavior below 10 K. The saturated resistance of our textured films is similar to that of the single crystals, suggesting that this conduction is from the surface and robust against grain boundary scatterings. Point contact spectroscopy (PCS) of the film using a superconducting tip displays both a Kondo Fano resonance and Andreev reflection, suggesting the existence of both an insulating Kondo lattice and metallic surface states.

arXiv comment21 pages, 4 figures

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Cited by in corpus (16)

• Kondo Breakdown in Topological Kondo Insulators
• Observation of perfect Andreev reflection due to Klein paradox in a topological superconducting state
• Surface state reconstruction in ion-damaged SmB_6
• Pressure-induced quantum phase transitions in topological insulator YbB6
• Opto-Electronic Characterization of Three Dimensional Topological Insulators
• Consistency between ARPES and STM measurements on SmB${}_6$
• Incomplete Protection of the Surface Weyl Cones of the Kondo Insulator SmB${}_6$: Spin Exciton Scattering
• Observation of the superconducting proximity effect in the surface state of SmB6 thin films
• Robust Surface States indicated by Magnetotransport in SmB6 Thin Films
• Signature of surface state coupling in thin films of the topological Kondo insulator SmB${}_6$ from anisotropic magnetoresistance
• Ultrafast terahertz spectroscopy study of Kondo insulating thin film SmB${}_6$: evidence for an emergent surface state
• Electrical properties of SmB${}_6$ thin films prepared by pulsed laser deposition from a stoichiometric SmB${}_6$ target
• An STM perspective on hexaborides: Surface states of the Kondo insulator SmB${}_6$
• Microwave Meissner Screening of Proximity coupled Topological Insulator / Superconductor Bilayers
• Low temperature resistivity studies of SmB6: Observation of twodimensional variable-range hopping conductivity
• Interacting topological phases in thin films of topological mirror Kondo insulators