NMR study of topological insulator Bi2Te3 in a wide temperature range

• Published in: Physics of the solid state 2017-12, Vol.59 (12), p.2331-2339
• Main Authors: Antonenko, A. O., Charnaya, E. V., Nefedov, D. Yu, Podorozhkin, D. Yu, Uskov, A. V., Bugaev, A. S., Lee, M. K., Chang, L. J., Naumov, S. V., Perevozchikova, Yu. A., Chistyakov, V. V., Huang, J. C. A., Marchenkov, V. V.
• Format: Article
• Language: English
• Subjects: Bismuth tellurides; Crystal structure; Current carriers; Dielectrics; Frequency shift; Intermetallic compounds; Line spectra; NMR; Nuclear magnetic resonance; Physics; Physics and Astronomy; Plates; Relaxation time; Solid State Physics; Spin-lattice relaxation; Tellurides; Tellurium; Temperature
• ISSN: 1063-7834; 1090-6460
• DOI: 10.1134/S1063783417120058

NMR studies of 125 Te in the topological insulator bismuth telluride Bi 2 Te 3 in a wide temperature range from room temperature to 12.5 K are performed. The pulsed NMR spectrometer Bruker Avance 400 is applied. The NMR spectra are obtained for the powder from Bi2Te3 single crystal and monocrystalline plates with the orientations c || B and c ⊥ B . At room temperature, the spectra consist of two lines related to two nonequivalent positions of tellurium nuclei Te1 and Te2. The parameters of the NMR frequency shift tensor are found from the powder spectrum. The temperature dependences of the spectra for the powder and plates with the orientation c ⊥ B agree with each other. The line shift with decreasing temperature is explained by the reduction of the Knight shift. The thermal activation energy of charge carriers is estimated. The spectra for the plates with the orientation c || B demonstrate peculiar behavior below 91 K. The spin-lattice relaxation time for the powder and monocrystalline plates with both orientations at room temperature is measured.