Regensburg 2019 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 61: Topology and Symmetry-Protected Materials (joint session O/MA/TT)

TT 61.1: Vortrag

Donnerstag, 4. April 2019, 15:00–15:15, H24

Structural and electronic characterization of thin Fe(Se,Te) films on the quaternary (Bi,Sb)Se_xTe_1−x 3D topological insulator — •Philipp Kagerer, Thiago R. F. Peixoto, Celso Fornari, Hendrik Bentmann, and Friedrich Reinert — Experimental Physics VII, Julius Maximilian University of Würzburg

The combination of an s-wave superconductor iron-chalcogenide and a 3D-topological insulator (TI) has become a vivid research topic in condensed matter physics due to the proposed emergence of bound Majorana zero modes at the interface under the presence of a time-reversal-breaking magnetic field [1]. Owing to its simple cubic structure and good growth properties, thin FeSeTe layers on (Bi,Sb)Se_xTe_1−x pose a promising platform to test this prediction.
Here we report on the epitaxial growth and characterization of thin layers of Fe(Se,Te) on a quaternary (Bi,Sb)(Se,Te) TI single-crystal. LEED and XPS experiments as well as STM and STS scans confirm the formation of a few monolayers of Fe(Se,Te) on top of the TI substrate. Using ARPES we show the arising of the FeSeTe valence bands near the Fermi level, along with the heavily n-doped band structure of the underlying TI. In addition, photon-energy-dependent and resonant measurements using synchrotron radiation allow a distinction between substrate and overlayer bands, and show indications for strong electron correlation and a Hubbard-gap in the material [2].
[1] L.Fu, C.L. Kane, Phys. Rev. Lett. 100, 096407 (2008)
[2] M.D.Watson et al., Phys. Rev. B 95, 081106(R) (2017)