Dresden 2017 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 60: Correlated Electrons: f-Electron Systems
TT 60.3: Talk
Thursday, March 23, 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 Vcf 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).