Tuning bulk and surface conduction in topological Kondo insulator SmB6

Abstract

Bulk and surface state contributions to the electrical resistance of single-crystal samples of the topological Kondo insulator compound SmB6 are investigated as a function of crystal thickness and surface charge density, the latter tuned by ionic liquid gating with electrodes patterned in a Corbino disk geometry on a single surface. By separately tuning bulk and surface conduction channels, we show conclusive evidence for a model with an insulating bulk and metallic surface states, with a crossover temperature that depends solely on the relative contributions of each conduction channel. The surface conductance, on the order of 100 e^2/h and electron-like, exhibits a field-effect mobility of 133 cm^2/V/s and a large carrier density of ~2x10^{14}/cm^2, in good agreement with recent photoemission results. With the ability to gate-modulate surface conduction by more than 25%, this approach provides promise for both fundamental and applied studies of gate-tuned devices structured on bulk crystal samples.

5 pages, 3 figures

References in corpus (3)

• Strong surface scattering in ultrahigh mobility Bi2Se3 topological insulator crystals
• 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

Cited by in corpus (23)

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• 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
• Bulk Rotational Symmetry Breaking in Kondo Insulator SmB6
• Spin- and angle-resolved photoemission on the topological Kondo Insulator candidate: SmB6
• Planar tunneling spectroscopy of the topological Kondo insulator SmB${}_6$
• Signature of surface state coupling in thin films of the topological Kondo insulator SmB${}_6$ from anisotropic magnetoresistance
• Ferromagnetism and glassiness on the surface of topological insulators
• Extraordinary Bulk Insulating Behavior in the Strongly Correlated Materials FeSi and FeSb${}_2$
• Probing the interplay between surface and bulk states in the topological Kondo insulator SmB${}_6$ through conductance fluctuation spectroscopy
• From bad metal to Kondo insulator: temperature evolution of the optical properties of SmB${}_6$
• Coulomb drag in topological materials
• Electrical detection of the inverse Edelstein effect on the surface of SmB${}_6$
• An STM perspective on hexaborides: Surface states of the Kondo insulator SmB${}_6$
• Low temperature resistivity studies of SmB6: Observation of twodimensional variable-range hopping conductivity
• Phase stability in SmB${}_6$
• Topological surface states in the Kondo insulator YbB${}_{12}$ revealed via planar tunneling spectroscopy
• Surface excitations relaxation in the Kondo insulator Sm${}_{1-x}$Gd${}_x$B${}_6$
• Persistence of correlation-driven surface states in SmB6 under pressure
• Intrinsic one-dimensional conducting channels in the Kondo insulator SmB6
• Electronic correlations and topology in Kondo insulator PuB${}_6$