Regensburg 2016 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 34: Topological Insulators (jointly with DS, HL, O, TT)

MA 34.4: Vortrag

Mittwoch, 9. März 2016, 15:45–16:00, H32

Surface preparation and momentum microscopy of the topological Kondo insulator SmB₆ — •Christian Tusche^{1, 2}, Martin Ellguth¹, Fumitoshi Iga³, and Shigemasa Suga^{2, 4} — ¹Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany — ²Peter Grünberg Institut PGI-6, Forschungszentrum Jülich, 52425 Jülich, Germany — ³College of Science, Ibaraki University, Japan — ⁴Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan

The strongly correlated rare-earth compound SmB₆ is believed to be a topological Kondo insulator, where a topologically non-trivial surface state lives in the hybridization gap at low temperatures. While most experimental studies rely on cleaved surfaces, high resolution- and spin resolved photoemission experiments [1] usually suffer from the short live time of the reactive surface at low temperatures.

Here we present the reproducible surface preparation of large high quality SmB₆ single crystals by in-situ Ar-ion sputtering and controlled annealing. In particular, Sm-rich or B-rich surface terminations are obtained by low (≈1080^∘C) or high (>1200^∘C) temperature annealing. Using a momentum microscope [2], wide wave vector regions are studied by photoemission with He-I (hν=21.2 eV) and laser (hν=6.0 eV) excitations, on the Sm-terminated surface. The results reveal localized f-electron resonances at E_F and strong hybridization, paving the way to measure detailed Fermi surface and valence band spin textures.

[1] Suga et al., J., Phys. Soc. Japan 83, 014705 (2014)

[2] C. Tusche, A. Krasyuk, J. Kirschner, Ultramicroscopy (2015)