Dresden 2017 – scientific programme
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MA: Fachverband Magnetismus
MA 43: Topological Insulators I (jointly with DS, HL, O, TT)
MA 43.1: Talk
Wednesday, March 22, 2017, 15:00–15:15, HSZ 401
Mn-doped topological insulators Bi2Te3 and Bi2Se3: an ab initio study of magnetism and transport properties — •Karel Carva1, Pavel Baláž1, Jakub Šebesta1, Josef Kudrnovský2, František Máca2, and Václav Drchal2 — 1Charles University, DCMP, Ke Karlovu 5, CZ-12116 Prague, Czech Republic — 2Institute of Physics, ASCR,Na Slovance 2, CZ-18221 Prague, Czech Republic
For the interpretation of experiments studying the Bi2Te3 and Bi2Se3 family of topological insulators it is necessary to include the native defects into the picture. Using similar methods one can study also the magnetic doping, which has attracted a lot of interest recently [1]. We calculate on an ab initio level the electronic structure of Bi2Te3 and Bi2Se3 doped by Mn at different possible positions and also in the presence of native antisites and vacancies. This provides for the first time a comprehensive map of possible behavior affecting strongly the bulk resistivity, carrier concentration and magnetism. It allows us to tune these properties, and also help to uncover the location of Mn atoms, since the substitutional or interstitial Mn placement exhibits strikingly different properties. Calculations indicate that the presence of interstitials may help to understand experimental observations[2].
Exchange interactions between Mn magnetic moments in bulk Mn-doped Bi2Te3 / Bi2Se3 have been calculated using ab initio methods. These results allow us to study the Curie temperatures by means of atomistic Monte Carlo simulations.
[1] Y. S. Hor et al., Phys. Rev. B 81, 195203 (2010)
[2] K. Carva et al., Phys. Rev. B 93, 214409 (2016)