Understanding Bulk Defects in Topological Insulators from Nuclear-Spin Interactions

Abstract

Non-invasive local probes are needed to characterize bulk defects in binary and ternary chalcogenides. These defects contribute to the non-ideal behavior of topological insulators. We have studied bulk electronic properties via ${}^{125}$Te NMR in Bi${}_2$Te${}_3$, Sb${}_2$Te${}_3$, Bi${}_{0.5}$Sb${}_{1.5}$Te${}_3$, Bi${}_2$Te${}_2$Se and Bi${}_2$Te${}_2$S. A distribution of defects gives rise to asymmetry in the powder lineshapes. We show how the Knight shift, line shape and spin-lattice relaxation report on carrier density, spin-orbit coupling and phase separation in the bulk. The present study confirms that the ordered ternary compound Bi${}_2$Te${}_2$Se is the best TI candidate material at the present time. Our results, which are in good agreement with transport and ARPES studies, help establish the NMR probe as a valuable method to characterize the bulk properties of these materials.

24 pages, 6 figures

References in corpus (25)

• Topological Insulators
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Topological invariants of time-reversal-invariant band structures
• Large bulk resistivity and surface quantum oscillations in the topological insulator Bi2Te2Se
• Band structure engineering in (Bi1-xSbx)2Te3 ternary topological insulators
• Stretched Exponential Relaxation Arising from a Continuous Sum of Exponential Decays
• Ambipolar Field Effect in Topological Insulator Nanoplates of (BixSb1-x)2Te3
• Controlling bulk conductivity in topological insulators: Key role of anti-site defects
• Low carrier concentration crystals of the topological insulator Bi${}_2$Te${}_2$Se
• Electronic structure and transport anisotropy of Bi2Te3 and Sb2Te3
• Fermi level tuning and a large activation gap achieved in the topological insulator Bi_{2}Te_{2}Se by Sn doping
• Thermal Expansion Coefficients of Bi${}_2$Se${}_3$ and Sb${}_2$Te${}_3$ Crystals from 10 K to 270 K
• Spin-orbit interaction effect in the electronic structure of \BiTe \ observed by angle-resolved photoemission spectroscopy
• Scanning Tunneling Microscopy of Defect States in the Semiconductor Bi${}_2$Se${}_3$
• Ternary Tetradymite Compounds as Topological Insulators
• Temperature dependence of Raman-active optical phonons in Bi_2Se_3 and Sb_2Te_3
• Bi2Te1.6S1.4 - a Topological Insulator in the Tetradymite Family
• NMR Probe of Metallic States in Nanoscale Topological Insulators
• Anomalous thermal expansion of Sb${}_2$Te${}_3$ topological insulator
• Nuclear magnetic resonance as a probe of electronic states of Bi2Se3
• Spin-lattice relaxation in bismuth chalcogenides
• A combined NMR and DFT study of Narrow Gap Semiconductors: The case of PbTe
• Nuclear-spin relaxation of ${}^{207}$Pb in ferroelectric powders
• Size-dependent properties of dithallium selenide
• The Interplay of Topological Surface and Bulk Electronic States in Bi2Se3

Cited by in corpus (8)

• Efficient Spin-Orbit Torque Switching with Non-Epitaxial Chalcogenide Heterostructures
• ${}^{77}$Se nuclear magnetic resonance of topological insulator Bi${}_2$Se${}_3$
• Tight-binding theory of NMR shifts in topological insulators Bi2Se3 and Bi2Te3
• Ionic and electronic properties of the topological insulator Bi${}_2$Te${}_2$Se investigated using $\beta$-detected nuclear magnetic relaxation and resonance of ${}^8$Li
• Topological insulator ring with magnetic impurities
• Local electronic and magnetic properties of the doped topological insulators Bi${}_2$Se${}_3$:Ca and Bi${}_2$Te${}_3$:Mn investigated using ion-implanted ${}^8$Li $\beta$-NMR
• Unusual ${}^{209}$Bi NMR quadrupole effects in topological insulator Bi${}_2$Se${}_3$
• NMR in an electric field: A bulk probe of the hidden spin and orbital polarizations