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arXiv · 1810.13419

Imaging emergent heavy Dirac fermions of a topological Kondo insulator

Harris Pirie·Yu Liu·A. Soumyanarayanan·Pengcheng Chen·Yang He·M. M. Yee·P. F. S. Rosa·J. D. Thompson·Dae-Jeong Kim·Z. Fisk·Xiangfeng Wang·J. Paglione·Dirk K. Morr·M. H. Hamidian·Jennifer E. Hoffman
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Abstract

Kondo insulators are primary candidates in the search for strongly correlated topological quantum phases, which may host topological order, fractionalization, and non-Abelian statistics. Within some Kondo insulators, the hybridization gap is predicted to protect a nontrivial topological invariant and to harbor emergent heavy Dirac fermion surface modes. We use high-energy-resolution spectroscopic imaging in real and momentum space on the Kondo insulator, SmB$_6$. On cooling through $T^*_Δ\approx$ 35 K we observe the opening of an insulating gap that expands to $Δ\approx$ 10 meV at 2 K. Within the gap, we image the formation of linearly dispersing surface states with effective masses reaching $m^* = (410\pm20)m_e$. We thus demonstrate existence of a strongly correlated topological Kondo insulator phase hosting the heaviest known Dirac fermions.

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Harris Pirie, Yu Liu, A. Soumyanarayanan, Pengcheng Chen, Yang He, M. M. Yee, P. F. S. Rosa, J. D. Thompson, Dae-Jeong Kim, Z. Fisk, Xiangfeng Wang, J. Paglione, Dirk K. Morr, M. H. Hamidian, Jennifer E. Hoffman. 2018-10-31. Imaging emergent heavy Dirac fermions of a topological Kondo insulator. https://doi.org/10.1038/s41567-019-0700-8

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