ERA-Chemistry: Spin-polarisierte topologische Isolatoren unter Druck
Zusammenfassung der Projektergebnisse
Bulk functional materials that can exhibit quantum effects under normal conditions are under intense spotlight nowadays, among them topological materials, 2D magnetic monolayers and frustrated magnets. Topological insulators (TIs) feature dissipationless electron transport on their surface thanks to protected spin-resolved surface states. First topological materials were discovered in 2009, and nowadays this is a burgeoning field of condensed-matter research. Particularly intriguing is a combination of non-trivial topology with magnetic order that could yield new types of topological (magneto)transport and possibilities to actively manipulate them. Material candidates are emerging hand in hand with theoretical advances. In our project, we have identified and experimentally characterized six new topological materials, namely, Bi2TeI, Bi3TeI, Bi2TeBr, Bi3TeBr, β-Bi4I4 and MnBi2Te4. Each group of compounds exhibits its special topological “signature”. The layered (Bi2)n(BiTeX)m compounds allow to trace the development of the topological properties from a trivial semiconductor (BiTeX) to a dual TI (Bi2TeX) and a topological metal (Bi3TeX) via enhancement of the interlayer interactions (hybridization of the states). β-Bi4I4 undergoes a transition into a superconducting phase under high pressure, which makes it an intriguing candidate for topological superconductivity. Last but not the least, the layered MnBi2Te4 is the first antiferromagnetic topological insulator with a periodic crystal structure. Thanks to their versatile magnetic and electronic properties, MnBi2Te4 and its derivatives may become a material platform for the realization of tunable topological quantum phenomena and foster applications in prototype devices for AFM spintronics, 2D magnets, etc. High-pressure conditions favor the formation of several novel manganese hydroxide halides, Mn(OH)X, X = Cl, Br, I, Mn5(OH)6Cl4, Mn5(OH)7I3 and Mn7(OH)10I4, that were first synthesized and structurally characterized in the current project. Calculations and magnetic measurements hint at competing magnetic ground states and proximity to magnetic frustration in some of these material that host Mn2+ cations on a triangular lattice. Extreme hydroscopicity challenges the physical measurements and calls for a specialized study. Furthermore, the new phases Mn5(BO3)3OH and Bi2(C3H5O3)2 with acentric crystal structures, as confirmed by X-ray diffraction and SHG measurements, were discovered as an unforeseen outcome of the highpressure studies.
Projektbezogene Publikationen (Auswahl)
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Prediction and observation of the first antiferromagnetic topological insulator
M. M. Otrokov, I. I. Klimovskikh, H. Bentmann, Z. S. Aliev, A. Zeugner, S. Gaß, A. U. B. Wolter, A. V. Koroleva, D. Estyunin, A. M. Shikin, M. Blanco-Rey, M. Hoffmann, A. Yu. Vyazovskaya, S. V. Eremeev, Yu. M. Koroteev, I. R. Amiraslanov, M. B. Babanly, N. T. Mamedov, N. A. Abdullayev, V. N. Zverev, E. F. Schwier, S. Kumar, A. Kimura, L. Petaccia, G. Di Santo, S. K. Moser, R. C. Vidal, T. R. F. Peixoto, C. H. Min, K. Treiber, S. Schatz, F. Reinert, A. Ernst, P. M. Echenique, A. Isaeva, E. V. Chulkov
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Modular Design with 2D Topological-Insulator Building Blocks: Optimized Synthesis and Crystal Growth, Crystal and Electronic Structures of BixTeI (x = 2, 3). Chem. Mater. 29 (2017), 1321–1337
A. Zeugner, M. Kaiser, P. Schmidt, T. V. Menshchikova, I. P. Rusinov, A. V. Markelov, W. Van den Broek, E.V. Chulkov, T. Doert, M. Ruck, A. Isaeva
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Pressure effect and superconductivity in β-Bi4I4 topological insulator. Phys. Rev. B. 95 (2017), 235149
A. Pisoni, R. Gaal, A. Zeugner, V. Falkowski, A. Isaeva, H. Huppertz, G. Autes, O. V. Yazyev, L. Forro
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Synthesis and characterization of the new manganese hydroxide chloride γ-Mn(OH)Cl. Eur. J. Chem. 2018(42) (2018), 4630–4637
V. Falkowski, A. Zeugner, A. Isaeva, M. Ruck, H. Huppertz
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Synthesis, crystal and topological electronic structures of new bismuth tellurohalides Bi2TeBr and Bi3TeBr. Chem. Mater. 30 (2018), 5272–5284
A. Zeugner, J. Teichert, M. Kaiser, T. V. Menshchikova, I. P. Rusinov, A. V. Markelov, E.V. Chulkov, T. Doert, M. Ruck, A. Isaeva
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Chemical aspects of the antiferromagnetic topological insulator MnBi2Te4. Chem. Mater. 31 (2019), 2795–2806
A. Zeugner, F. Nietschke, A. U. B. Wolter, S. Gaß, R.C. Vidal, T.R.F. Peixoto, D. Pohl, Ch. Damm, A. Lubk, R. Hentrich, S. K. Moser, C. Fornari, C.H. Min, S. Schatz, K. Kißner, M. Ünzelmann, M. Kaiser, F. Scaravaggi, B. Rellinghaus, K. Nielsch, Ch. Heß, B. Büchner, F. Reinert, H. Bentmann, O. Oeckler, M. Ruck, A. Isaeva
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Synthesis and characterization of the manganese hydroxide halides Mn(OH)X (X = Br, I) and crystal structure of trans-MnBr2·4H2O. Z. Anorg. Allg. Chem. (2019)
V. Falkowski, A. Zeugner, A. Isaeva, K. Wurst, M. Ruck, H. Huppertz
