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Incorporation of europium in Bi2Te3 topological insulator epitaxial films

DOI: 10.1021/acs.jpcc.0c05077 DOI Help

Authors: Celso I. Fornari (Universität Würzburg; Instituto Nacional de Pesquisas Espaciais) , Hendrik Bentmann (Universität Würzburg) , Sergio L. Morelhao (Universidade de São Paulo) , Thiago R. F. Peixoto (Universität Würzburg) , Paulo Rappl (Instituto Nacional de Pesquisas Espaciais) , Abdul Tcakaev (Universität Würzburg) , Volodymyr Zabolotnyy (Universität Würzburg) , Martin Kamp (Universität Würzburg) , Tien-lin Lee (Diamond Light Source) , Chul-hee Min (Universität Würzburg) , Philipp Kagerer (Universität Würzburg) , Raphael Vidal (Universität Würzburg) , Anna Isaeva (Technische Universität Dresden; Leibniz IFW Dresden; Würzburg-Dresden Cluster of Excellence ct.qmat) , Michael Ruck (Technische Universität Dresden; Max Planck Institute for Chemical Physics of Solids; Würzburg-Dresden Cluster of Excellence ct.qmat) , Vladimir Hinkov (Universität Würzburg) , Friedrich Reinert (Universität Würzburg) , Eduardo Abramof (Instituto Nacional de Pesquisas Espaciais)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Journal Of Physical Chemistry C

State: Published (Approved)
Published: June 2020

Abstract: In the field of topological materials, the interaction between band topology and magnetism remains a current frontier for the advance of new topological states and spintronic functionalities. Doping with rare-earth elements with large magnetic moment is a current approach to exploit the phenomenology of such interaction. However, dopant solubility into the main matrix plays a major role. In this sense, the present work is focused on elucidating how Eu incorporates into Bi2Te3 lattice as a function of doping. This work reports a systematic investigation of the structural and electronic properties of bismuth telluride epitaxial layers doped with Eu. Bi2Te3 films were grown by molecular beam epitaxy (MBE) on (111) BaF2 substrates with nominal Eu doping ranging from 0 % up to 9 %. X-ray diffraction (XRD) analysis and scanning transmission electron microscopy (TEM) reveal that Eu atoms enter substitutionally on Bi sites up to 4 % of Eu doping. In contrast, the 9 % Eu-doped sample contains epitaxially oriented nanoclusters of EuTe. X ray photoelectron (XPS) and absorption (XAS) spectroscopies show that Eu atoms enter into the Bi2Te3 crystal matrix in the divalent Eu2+ state for all Eu concentrations. Angle resolved photoemission (ARPES) experiments indicate that the topological surface state is preserved in the presence of the local magnetic moments introduced by the Eu impurities.

Journal Keywords: topological insulator; magnetic doping; molecular beam epitaxy; bismuth telluride; europium

Subject Areas: Physics, Chemistry, Materials

Instruments: I09-Surface and Interface Structural Analysis

Other Facilities: LNLS; Beamline P04 at DESY PETRA III