Observation of Distinct Bulk and Surface Chemical Environments in a Topological Insulator under Magnetic Doping

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• 作者：Ivana Vobornik ; Giancarlo Panaccione ; Jun Fujii ; Zhi-Huai Zhu ; Francesco Offi ; Benjamin R. Salles ; Francesco Borgatti ; Piero Torelli ; Jean Pascal Rueff ; Denis Ceolin ; Alberto Artioli ; Manju Unnikrishnan ; Giorgio Levy ; Massimiliano Marangolo ; Mamhoud Eddrief ; Damjan Krizmancic ; Huiwen Ji ; Andrea Damascelli ; Gerrit van der Laan ; Russell G. Egdell ; Robert J. Cava
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：June 12, 2014
• 年：2014
• 卷：118
• 期：23
• 页码：12333-12339
• 全文大小：375K
• 年卷期：v.118,no.23(June 12, 2014)
• ISSN：1932-7455

文摘

The influence of magnetic dopants on the electronic and chemical environments in topological insulators (TIs) is a key factor when considering possible spintronic applications based on topological surface state properties. Here we provide spectroscopic evidence for the presence of distinct chemical and electronic behavior for surface and bulk magnetic doping of Bi₂Te₃. The inclusion of Mn in the bulk of Bi₂Te₃ induces a genuine dilute ferromagnetic state, with reduction of the bulk band gap as the Mn content is increased. Deposition of Fe on the Bi₂Te₃ surface, on the other hand, favors the formation of iron telluride already at coverages as low as 0.07 monolayer, as a consequence of the reactivity of the Te-rich surface. Our results identify the factors that need to be controlled in the realization of magnetic nanosystems and interfaces based on TIs.