Quantum oscillations in Kondo Insulator SmB$_6$

TL;DR

This paper reports the observation of quantum oscillations in the Kondo insulator SmB$_6$, revealing a two-dimensional Dirac surface state through torque magnetometry, providing evidence for topological surface states.

Contribution

It demonstrates the existence of a 2D Dirac surface state in SmB$_6$ by resolving Landau Levels and Fermi surface topology, a novel insight into its topological nature.

Findings

Detection of quantum oscillations indicating a 2D surface state

Identification of a Dirac electronic state with Landau Level analysis

Evidence supporting topological surface states in SmB$_6"

Abstract

In Kondo insulator samarium hexaboride SmB$_6$, strong correlation and band hybridization lead to an insulating gap and a diverging resistance at low temperature. The resistance divergence ends at about 5 Kelvin, a behavior recently demonstrated to arise from the surface conductance. However, questions remain whether and where a topological surface state exists. Quantum oscillations have not been observed to map the Fermi surface. We solve the problem by resolving the Landau Level quantization and Fermi surface topology using torque magnetometry. The observed Fermi surface suggests a two dimensional surface state on the (101) plane. Furthermore, the tracking of the Landau Levels in the infinite magnetic field limit points to -1/2, which indicates a 2D Dirac electronic state.