Unconventional Fermi surface in an insulating state

摘要: Insulators occur in more than one guise; a recent finding was class of topological insulators, which host conducting surface juxtaposed with an insulating bulk. Here, we report the observation unusual state electrically bulk that simultaneously yields quantum oscillations characteristics unconventional Fermi liquid. We present oscillation measurements magnetic torque high-purity single crystals Kondo insulator SmB6, reveal frequencies characteristic large three-dimensional conduction electron similar to metallic rare earth hexaborides such as PrB6 and LaB6. The amplitude strongly increases at low temperatures, appearing strikingly variance conventional behavior.