Incipient antiferromagnetism in the Eu-doped topological insulator Bi2Te3
Creators
-
Rüßmann, Philipp1
*
- Tcakaev, Abdul2
- Zabolotnyy, Volodymyr B.2
- Fornari, Celso I.3, 4, 5
- Peixoto, Thiago R. F.3, 4
- Stier, Fabian2
- Dettbarn, Michael2
- Kagerer, Philipp3, 4
- Weschke, Eugen6
- Schierle, Enrico6
- Bencok, Peter7
- Rappl, Paulo H. O.5
- Abramof, Eduardo5
- Bentmann, Hendrik3, 4
- Goering, Eberhard8
- Reinert, Friedrich3, 4
- Hinkov, Vladimir2
- 1. Peter Grünberg Institut and Institute for Advanced Simulation (PGI-1/IAS-1), Forschungszentrum Jülich and JARA, D-52425 Jülich
- 2. Experimentelle Physik IV and Röntgen Research Center for Complex Materials (RCCM), Fakultät für Physik und Astronomie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
- 3. Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Fakultät für Physik und Astronomie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
- 4. Würzburg-Dresden Cluster of Excellence ct.qmat, Germany
- 5. Laboratório Associado de Sensores e Materiais, Instituto Nacional de Pesquisas Espaciais, Sao José dos Campos, 12245-970, Sao Paulo, Brazil
- 6. Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, D-12489 Berlin, Germany
- 7. Diamond Light Source, Didcot OX11 0DE, United Kingdom
- 8. Max-Planck-Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
* Contact person
Description
Rare earth ions typically exhibit larger magnetic moments than transition metal ions and thus promise the opening of a wider exchange gap in the Dirac surface states of topological insulators. Yet, in a recent photoemission study of Eu-doped Bi2Te3 films, the spectra remained gapless down to T=20K. Here, we scrutinize whether the conditions for a substantial gap formation in this system are present by combining spectroscopic and bulk characterization methods with theoretical calculations. For all studied Eu doping concentrations, our atomic multiplet analysis of the M4,5 x-ray absorption and magnetic circular dichroism spectra reveals a Eu2+ valence and confirms a large magnetic moment, consistent with a 4f7 8S7/2 ground state. At temperatures below 10K, bulk magnetometry indicates the onset of antiferromagnetic (AFM) ordering. This is in good agreement with density functional theory, which predicts AFM interactions between the Eu impurities. Our results support the notion that antiferromagnetism can coexist with topological surface states in rare-earth doped Bi2Te3 and call for spectroscopic studies in the kelvin range to look for novel quantum phenomena such as the quantum anomalous Hall effect.
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References
Preprint (Paper where the data is discussed) A. Tcakaev, V. B. Zabolotnyy, C. I. Fornari, P. Rüßmann, T. R. F. Peixoto, F. Stier, M. Dettbarn, P. Kagerer, E. Weschke, E. Schierle, P. Bencok, P. H. O. Rappl, E. Abramof, H. Bentmann, E. Goering, F. Reinert, V. Hinkov, Incipient antiferromagnetism in the Eu-doped topological insulator Bi2Te3, arXiv:2009.11733 (2020)
Software (DFT code used in the calculations) The JuKKR developers, JuKKR code suite for density functional calculations (2020)
Software (The aiida-kkr plugin) P. Rüßmann, J. Broeder, JuDFTteam/aiida-kkr v1.1.10, Zenodo (2020), doi: 10.5281/zenodo.3663525
Software (The aiida-kkr plugin) P. Rüßmann, J. Broeder, JuDFTteam/aiida-kkr v1.1.10, Zenodo (2020)
Preprint (Paper where the aiida-kkr plugin is introduced) P. Rüßmann, F. Bertoldo, S. Blügel, The AiiDA-KKR plugin and its application to high-throughput impurity embedding into a topological insulator, arXiv:2003.08315 (2020)