NMR Probe of Metallic States in Nanoscale Topological Insulators

Abstract

A 125Te NMR study of bismuth telluride nanoparticles as function of particle size revealed that the spin-lattice relaxation is enhanced below 33 nm, accompanied by a transition of NMR spectra from single to bimodal regime. The satellite peak features a negative Knight shift and higher relaxivity, consistent with core polarization from p-band carriers. Whereas nanocrystals follow a Korringa law in the range 140-420K, micrometer particles do so only below 200K. The results reveal increased metallicity of these nanoscale topological insulators in the limit of higher surface-to-volume ratios.

arXiv comment17 pages, 4 figures, 1 table

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• Nanoscale $\beta$-Nuclear Magnetic Resonance Depth Imaging of Topological Insulators
• Surface states and local spin susceptibility in doped three-dimensional topological insulators with odd-parity superconducting pairing symmetry
• 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
• Site-Specific Contributions to the Band Inversion in a Topological Crystalline Insulator
• Anomalous nuclear magnetic resonance spectra in Bi${}_2$Se${}_3$ nanowires
• ${}^{239}$Pu nuclear magnetic resonance in the candidate topological insulator PuB${}_4$
• Unusual ${}^{209}$Bi NMR quadrupole effects in topological insulator Bi${}_2$Se${}_3$
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• ZrOsSi: A $Z_2$ topological metal with a superconducting ground state
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• Splitting of the topologically-protected Dirac cone without breaking time reversal symmetry
• NMR Evidence for the Topologically Nontrivial Nature in a Family of Half-Heusler Compounds