Screened Moments in a Kondo insulator: extrinsic origin of in-gap states in SmB6

ORAL

Abstract


The small gap insulator SmB6 has long been known to have thermodynamic properties at odds with being an insulator, yet the extensive search for low-energy phenomena which could explain this has remained elusive and controversial even after 50 years of research into its unconventional nature. We have observed a Kondo impurity-like moment screening effect in the insulating state of nominally pure and Gd-doped SmB6 via heat capacity, magnetization, and resistivity measurements. High-resolution neutron scattering on the low energy regime confirms directly that no coherent magnetism is evident below the long-lived 13 meV spin exciton, restricting proposals of intrinsic neutral low-energy magnetic excitations.b We infer that the mixed valence, strongly-correlated nature of SmB6 elicits extreme sensitivity to impurities and defects which induce metal-like bulk properties.

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Presenters

  • Wesley Fuhrman

    Johns Hopkins University

Authors

  • Wesley Fuhrman

    Johns Hopkins University

  • Juan Chamorro

    Johns Hopkins University

  • Pavel Alekseev

    Kurchatov Institute

  • Jean-Michel Mignot

    CEA-CNRS

  • Thomas Keller

    Max Planck

  • Jose Rodriguez

    NIST, NIST Center for Neutron research, NCNR, NIST, NIST NCNR, NIST Center for Neutron Research

  • Yiming Qiu

    NIST, NIST Center for Neutron Research, National Institute of Standards and Technology, NIST NCNR

  • Predrag Nikolic

    George Mason University

  • Tyrel McQueen

    Johns Hopkins University, Institute for Quantum Matter, Johns Hopkins University, Department of Chemistry , Johns Hopkins University, The Johns Hopkins University

  • Collin Broholm

    Johns Hopkins University, Institute for Quantum Matter, Johns Hopkins University