Observation of hidden atomic order at the interface between Fe and topological insulator Bi2Te3

Author(s)
Jaime Sanchez-Barriga, Ilya I. Ogorodnikov, Mikhail V. Kuznetsov, Andrey A. Volykhov, Fumihiko Matsui, Carolien Callaert, Joke Hadermann, Nikolay I. Verbitskiy, Roland J. Koch, Andrei Varykhalov, Oliver Rader, Lada V. Yashina
Abstract

To realize spintronic devices based on topological insulators (TIs), well-defined interfaces between magnetic metals and TIs are required. Here, we characterize atomically precisely the interface between the 3d transition metal Fe and the TI Bi

2Te

3 at different stages of its formation. Using photoelectron diffraction and holography, we show that after deposition of up to 3 monolayers Fe on Bi

2Te

3 at room temperature, the Fe atoms are ordered at the interface despite the surface disorder revealed by our scanning-tunneling microscopy images. We find that Fe occupies two different sites: a hollow adatom deeply relaxed into the Bi

2Te

3 quintuple layers and an interstitial atom between the third (Te) and fourth (Bi) atomic layers. For both sites, our core-level photoemission spectra and density-functional theory calculations demonstrate simultaneous chemical bonding of Fe to both Te and Bi atoms. We further show that upon deposition of Fe up to a thickness of 20 nm, the Fe atoms penetrate deeper into the bulk forming a 2-5 nm interface layer containing FeTe. In addition, excessive Bi is pushed down into the bulk of Bi

2Te

3 leading to the formation of septuple layers of Bi

3Te

4 within a distance of ∼25 nm from the interface. Controlling the magnetic properties of the complex interface structures revealed by our work will be of critical importance when optimizing the efficiency of spin injection in TI-based devices.

Organisation(s)
Electronic Properties of Materials
External organisation(s)
Helmholtz-Zentrum Berlin für Materialien und Energie, Russian Academy of Sciences, Anuchin Research Institute and Museum of Anthropology, Nara Institute of Science and Technology (NAIST), University of Antwerp, Lawrence Berkeley National Laboratory
Journal
Physical Chemistry Chemical Physics
Volume
19
Pages
30520-30532
No. of pages
13
ISSN
1463-9076
DOI
https://doi.org/10.1039/c7cp04875k
Publication date
12-2017
Peer reviewed
Yes
Austrian Fields of Science 2012
104006 Solid state chemistry, 103018 Materials physics, 103009 Solid state physics, 103020 Surface physics
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/observation-of-hidden-atomic-order-at-the-interface-between-fe-and-topological-insulator-bi2te3(39caf9e0-7047-4d6c-8ca2-97349ab30203).html