Electron Spin resonance of Gd3+ in three dimensional topological insulator Bi2Se3. (18th March 2015)

• Record Type: Journal Article
• Authors: Garitezi, T M; Lesseux, G G; Jesus, C B R; Grant, T; Fisk, Z; Urbano, R R; Rettori, C; Pagliuso, P G
• Is Part Of: Journal of physics. Number 592 (2015)
• Page Start: 012125
• Publication Date: 2015-03-18
• Subjects: Physics -- Congresses; 530.5
• DOI: 10.1088/1742-6596/592/1/012125
• Languages: English
• ISSNs: 1742-6588

Abstract

Abstract: Bi2 Se3 has 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 Gd 3+ doped ( x ≈ 0.01) Bi2 Se3 single crystal grown from stoichiometric melt. For the studied crystals, our preliminary results revealed a partly resolved Gd 3+ fine structure spectrum with Dysonian (metallic character) lines. At room temperature, the central line has a g ≈ 1.98, a linewidth Δ H ≈ 95 G and the spectra have a overall splitting of roughly 1300 Oe. As the temperature is decreased, the Gd 3+ ESR Δ H of the central line presents a very small Korringa-like behavior b = Δ H /Δ T ≈ 0.013 Oe/K and nearly T -independent g -value. However, for T ≲ 40 K, Δ H shows a stronger narrowing effect evolving to Korringa-like behavior ( b ≈ 0.15 Oe/K) for T ≲ 30 K. Concomitantly with the change in Δ H behavior, the Gd 3+ 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.