SmB: Topological insulator or semiconductor with valence-fluctuation induced hopping transport?
arXiv:0710.1159 · doi:10.1016/j.ssc.2014.07.014
Abstract
We advert to the fact that presence of valence fluctuations (VFs) in semiconductors with in-gap impurity bands unconditionally leads to dynamical changes (fluctuations) of energies of localized impurity states. We provide arguments that in the impurity subnetwork consisting of centers having energy levels fluctuating around the Fermi energy there exist favorable conditions for hops from occupied states to empty states of less energy. Consequently, we propose original valence-fluctuation induced hopping mechanism as a new possibility to explain unusual metallic-like conduction of SmB and other Kondo insulators experimentally observed at lowest temperatures. Interestingly, the proposed mechanism infers enhanced metallic-like surface conductivity of SmB, what resembles a characteristic property of topological insulator, and is in agreement with experimental observations attempting to prove the existence of topologically protected surface state in SmB.
17 pages, 3 figures, accepted to Solid State Communications
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Cited by in corpus (5)
- Formation and condensation of excitonic bound states in the generalized Falicov-Kimball model
- Surface and bulk components of electrical conductivity in the (presumably special topological) Kondo insulator SmB6 at lowest temperatures
- Electrical properties of SmB thin films prepared by pulsed laser deposition from a stoichiometric SmB target
- Low temperature resistivity studies of SmB6: Observation of twodimensional variable-range hopping conductivity
- SmB6: A material with anomalous energy distribution function of charge carriers?