Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 60: Correlated Electrons: f-Electron Systems
TT 60.2: Vortrag
Donnerstag, 23. März 2017, 09:45–10:00, HSZ 201
Investigation of the energy scales in SmB6 by scanning tunneling microscopy — •Lin Jiao1, Sahana Rößler1, Dae-Jeong Kim2, Liu Hao Tjeng1, Zachary Fisk2, Frank Steglich1, and Steffen Wirth1 — 1Max-Planck-Institute for Chemical Physics of Solids, Dresden, Germany — 2Department of Physics, University of California, Irvine, California, USA
SmB6 has been proposed as a topological Kondo insulator, which possesses topologically protected nontrivial surface states inside the bulk hybridization gap. By conducting scanning tunneling microscopy and spectroscopy, we are able to perform local measurements on well identified non-reconstructed (001) surfaces. Above ∼7 K and up to 80 K, the electronic states in SmB6 are governed by the Kondo effect of the bulk [1]. At temperatures as low as 0.35 K, we observed several well-resolved states within the hybridization gap (±20 meV) of SmB6 for the first time [2]. These states possess sharp peak-like features with a strong temperature dependence below 7 K, which indicates an additional energy scale at the surface of SmB6, in line with a suppression of the Kondo effect at the surface. These high resolution data offer the opportunity to directly compare our spectroscopy with band structure calculations, and analyze their surface or bulk origin, which may help reconciling many contradicting assertions in this material.
[1] S. Rößler et al., Proc. Natl. Acad. Sci. USA 111, 4798 (2014)
[2] L. Jiao et al., Nat. Commun. 7, 13762 (2016)