Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 60: Correlated Electrons: f-Electron Systems

TT 60.3: Vortrag

Donnerstag, 23. März 2017, 10:00–10:15, HSZ 201

Subsurface electronic structure of the mixed-valent SmB₆ — •Chul-Hee Min¹, Peter Lutz¹, Katharina Treiber¹, Thiago R.F. Peixoto¹, Hendrik Bentmann¹, Boyoun Kang², Beongki Cho², and Friedrich Reinert¹ — ¹Universität Würzburg, EP7, Würzburg, Germany — ²School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea

Strongly correlated topological insulators are expected to show drastically distinct phenomena near the surface region ^1,2 because the hybridization strength V_cf of bulk and surface can be different ³. We present an investigation on the probing depth dependence of 4f states and 3d core-levels in samarium hexaboride (SmB₆) to identify the unique subsurface electronic properties. From both angle- and photon energy-dependent studies, we estimate the thickness of the subsurface layer, which shows different Sm valence from the bulk one. Based on our estimation, we discuss about the surface, subsurface and bulk contributions in the 4f spectra. Our results indicate that at least two-component are present in the soft x-ray 4f spectra, which brings the size of the bulk gap of SmB₆ into question.

[1] Y. Xu, et al., Phys. Rev. Lett. 116, 246403 (2016).

[2] O. Erten, et al. Phys. Rev. Lett. 116, 046403 (2016).

[3] J. Allen, Phil. Mag. 96, 3227 (2016).