Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 12: Nanostructures at Surfaces II: Designer Structures and Surfaces

O 12.6: Vortrag

Montag, 1. April 2019, 16:30–16:45, H15

Structural and electronic characterization of Eu-doped Bi2Te3 epitaxial films — •Celso I. Fornari1, Hendrik Bentmann1, Thiago R. F. Peixoto1, Paulo Rappl2, Eduardo Abramof2, Sérgio Morelhão3, Martin Kamp4, and Friedrich Reinert11Experimentelle Physik VII, Würzburg — 2Instituto Nacional de Pesquisas Espaciais, Brazil — 3Universidade de São Paulo, Brazil — 4Physikalisches Institut, Würzburg

Bismuth telluride is a simple model for three-dimensional topological insulators (TIs) with a single Dirac cone at the surface. The topological surface states are protected against backscattering due to small imperfections in the lattice or from scattering due to non-magnetic impurities by time reversal symmetry (TRS). However, to unlock novel physical phenomena, it is a prerequisite to break TRS. In this sense, TIs have been investigated by doping with transition metals or rare earth elements and by proximity effect to magnetic layers or substrates.

In this work, we report on a systematic study of the MBE growth of europium doped bismuth telluride films on (111) BaF2. The small lattice mismatch (0.04 %) to bismuth telluride makes this material a suitable substrate to grow high-quality thin films. Films with nominal Eu concentration ranging from 0 (reference) up to 9 % were produced. Using high-resolution X-ray diffraction (HR-XRD), transmission electron microscopy (TEM) and angle-resolved photoemission spectroscopy (ARPES), evidences of Eu entering Bi sites up to concentrations around 4 % were obtained with a preserved Dirac cone at the surface.

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