Surface and bulk components of electrical conductivity in the (presumably special topological) Kondo insulator SmB6 at lowest temperatures

Abstract

Samarium hexaboride (SmB6) has recently been considered to be a topological Kondo insulator (TKI), the first strongly correlated electron system to exhibit topological surface conduction states. In this contribution, results of electrical resistivity measurements between 80 K and 0.08 K of various SmB6 single crystalline samples are presented, analyzed and discussed. The received results imply that the residual conductivity of SmB6 below about 4 K is of non-activated (metallic-like) nature. It is shown that this metallic-like behavior can be attributed both to surface (2D) conduction states, as may be expected in case of a topological insulator, as well as to the highly correlated many-body (3D) bulk ground state which is formed within the gap of this compound. From this it follows that in SmB6, where surface conductivity states are clearly present, there is in parallel also a bulk contribution to residual electrical conductivity originating from the strongly correlated electron system with valence fluctuations. This raises the question whether SmB6 does not form a new / special type of topological insulator in which in the energy gap besides the surface conduction states, there is also a conducting narrow in-gap band originating from the bulk strongly correlated electron system.

9 pages, 5 figures

References in corpus (11)

• An equivalent expression of Z2 Topological Invariant for band insulators using Non-Abelian Berry's connection
• Topological Kondo Insulators
• Wannier representation of Z_2 topological insulators
• Surface electronic structure of the topological Kondo insulator candidate correlated electron system SmB6
• Low-temperature surface conduction in the Kondo insulator SmB${}_6$
• A theory of Topological Kondo Insulators
• Hybridization, Inter-Ion Correlation, and Surface States in the Kondo Insulator SmB6
• Theory of Electronic Ferroelectricity
• The energy gap of intermediate-valent SmB6 studied by point-contact spectroscopy
• Classical Mechanics without Absolute Space
• SmB${}_6$: Topological insulator or semiconductor with valence-fluctuation induced hopping transport?

Cited by in corpus (5)

• Observation of a well-defined hybridization gap and in-gap states on the SmB6 (001) surface
• Topological surface conduction in Kondo insulator YbB${}_{12}$
• Quantum spin fluctuations in the bulk insulating state of pure and Fe-doped SmB6
• Fragility of the Kondo insulating gap against disorder: relevance to recent puzzles in topological Kondo insulators
• Bulk transport paths through defects in floating zone and Al flux grown SmB${}_6$