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Nanostructure associated properties of FexBi2Se3 single crystals

Authors: Zich Jan | Čermák Patrik | Navrátil Jiří | Čermák Šraitrová Kateřina | Drašar Čestmír

Year: 2024

Type of publication: ostatní - přednáška nebo poster

Page from-to: nestránkováno

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Language	Name	Abstract	Keywords
eng	Nanostructure associated properties of FexBi2Se3 single crystals	Over a decade ago, narrow gap semiconductor Bi2Se3 has been identified as one of 3D topological insulators. These materials show insulating behavior in bulk but has conductive states on surfaces or edges. These surface or edge states are not just ordinary conducting states, as they are topologically protected by the material's symmetries. This leads to robust-ness against impurities and defects that would typically scatter electrons in ordinary materi-als.1 To improve transport properties of Bi2Se3 better understand the interactions between both magnetic and nonmagnetic impurities and the topological surface states, researchers have turned their attention to doping. It was observed that some impurities can induce super-conductivity within these materials.2 In our work, Fe-doped single crystals of nominal composition FexBi2Se3 (x=0, 0.005, 0.01, 0.02, 0.04, 0.1) and Bi2-xFexSe3 (x=0.005 and 0.01) were grown using the free melt crystallization (FMC) method. To confirm crystallographic quality of prepared crystals and rule out other superconducting phases, HRXRD and LRXRD were performed. Low tempera-ture transport and magnetotransport properties were also measured with focus on supercon-ductivity. To support our experimental findings, we used DFT calculations to identify role of Fe substitutional defects and its d electrons in Bi2Se3doped samples.3 We have concluded that Fe-intercalated Bi2Se3 exhibits superconductivity, pro-nounced Shubnikov de Haas (SdH) oscillations, high carrier mobility, and features of 2D transport in the sample volume even for very low concentration of Fe (x=0.02). Transport properties of Bi2Se3 are highly influenced by defect structure of material itself. Thus, when analyzing the physical properties of both doped and undoped Bi2Se3 single crystals, their domain structure should always be considered.