Intrinsic Bulk Quantum Oscillations in a Bulk Unconventional Insulator SmB6

Máté Hartstein; Hsu Liu; Yu-Te Hsu; Beng S Tan; Monica Ciomaga Hatnean; Geetha Balakrishnan; Suchitra E Sebastian

doi:10.1016/j.isci.2020.101632

Intrinsic Bulk Quantum Oscillations in a Bulk Unconventional Insulator SmB₆

iScience. 2020 Oct 1;23(11):101632. doi: 10.1016/j.isci.2020.101632. eCollection 2020 Nov 20.

Authors

Máté Hartstein¹, Hsu Liu¹, Yu-Te Hsu¹, Beng S Tan¹, Monica Ciomaga Hatnean², Geetha Balakrishnan², Suchitra E Sebastian¹

Affiliations

¹ Cavendish Laboratory, Cambridge University, Cambridge CB3 0HE, UK.
² Department of Physics, University of Warwick, Coventry CV4 7AL, UK.

Abstract

The finding of bulk quantum oscillations in the Kondo insulator SmB₆ proved a considerable surprise. Subsequent measurements of bulk quantum oscillations in other correlated insulators including YbB₁₂ lent support to our discovery of a class of bulk unconventional insulators that host bulk quantum oscillations. Here we perform a series of experiments to examine evidence for the intrinsic character of bulk quantum oscillations in floating zone-grown single crystals of SmB₆ that have been the subject of our quantum oscillation studies. We present results of thermodynamic, transport, and composition analysis experiments on pristine floating zone-grown single crystals of SmB₆ and compare quantum oscillations with metallic LaB₆ and elemental aluminum. These results establish the intrinsic origin of quantum oscillations from the insulating bulk of floating zone-grown SmB₆. The similarity of the Fermi surface in insulating SmB₆ with the conduction-electron Fermi surface in metallic hexaborides is at the heart of a theoretical mystery.

Keywords: Condensed Matter Physics; Quantum Solids; Strongly Correlated Electron Systems.