Electron Spin resonance of Gd3+ in three dimensional topological insulator Bi2Se3

International Conference on Strongly Correlated Electron Systems 2014

Garitezi, T.M.^1 ; Lesseux, G.G.^1 ; Jesus, C.B.R.^1 ; Grant, T.^2 ; Fisk, Z.^2 ; Urbano, R.R.^1 ; Rettori, C.^1 ; Pagliuso, P.G.^1

Instituto de Física Gleb Wataghin, UNICAMP, Campinas

13083-859, SP, Brazil^1

University of California, Irvine

CA

92697-4573, United States^2

关键词: Complementary data;    Electron spin resonance measurements;    Exotic properties;    Fine structures;    G-values;    Macroscopic measurements;    Metallic surface;    Topological insulators;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/592/1/012125/pdf
DOI  :  10.1088/1742-6596/592/1/012125

来源: IOP

【 摘 要 】

Bi2Se3has been claimed to be a three dimensional topological insulator (TI) with topologically protected metallic surface states with exotic properties. We have performed electron spin resonance (ESR) measurements on Gd3+doped (x ≈ 0.01) Bi2Se3single crystal grown from stoichiometric melt. For the studied crystals, our preliminary results revealed a partly resolved Gd3+fine structure spectrum with Dysonian (metallic character) lines. At room temperature, the central line has a g ≈ 1.98, a linewidth ΔH ≈ 95 G and the spectra have a overall splitting of roughly 1300 Oe. As the temperature is decreased, the Gd3+ESR ΔH of the central line presents a very small Korringa-like behavior b =ΔH/ΔT ≈ 0.013 Oe/K and nearly T-independent g-value. However, for T40 K, ΔH shows a stronger narrowing effect evolving to Korringa-like behavior (b ≈ 0.15 Oe/K) for T30 K. Concomitantly with the change in ΔH behavior, the Gd3+central line g value starts to decrease reaching a value of 1.976 at T =4.2 K. The ESR results are discussed in terms of possible effects of protected topological surface states enlightened by complementary data from macroscopic measurements.