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arXiv · 1504.01179

Incomplete Protection of the Surface Weyl Cones of the Kondo Insulator SmB$_6$: Spin Exciton Scattering

G. A. Kapilevich·P. S. Riseborough·A. X. Gray·M. Gulacsi·Tomasz Durakiewicz·J. L. Smith
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Abstract

The compound SmB$_6$ is a Kondo Insulator, where the lowest-energy bulk electronic excitations are spin excitons. It also has surface states that are subjected to strong spin-orbit coupling. It has been suggested that SmB$_6$ is also a topological insulator. Here we show that, despite the absence of time-reversal symmetry breaking and the presence of strong spin-orbit coupling, the chiral spin texture of the Weyl cone is not completely protected. In particular, we show that the spin-exciton mediated scattering produces features in the surface electronic spectrum at energies separated from the surface Fermi energy by the spin-exciton energy. Despite the features being far removed from the surface Fermi energy, they are extremely temperature dependent. The temperature variation occurs over a characteristic scale determined by the dispersion of the spin exciton. The structures may be observed by electron spectroscopy at low temperatures.

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G. A. Kapilevich, P. S. Riseborough, A. X. Gray, M. Gulacsi, Tomasz Durakiewicz, J. L. Smith. 2015-04-06. Incomplete Protection of the Surface Weyl Cones of the Kondo Insulator SmB$_6$: Spin Exciton Scattering. https://doi.org/10.1103/physrevb.92.085133

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