Anharmonic rattling vibrations effects in the ESR of Er3+ doped SmB6 Kondo insulator

Journal Article · Mon Jan 23 00:00:00 EST 2017 · AIP Advances

DOI:https://doi.org/10.1063/1.4974914· OSTI ID:1349331

Lesseux, G. G. ^[1]; Rosa, P. F. S. ^[2]; Fisk, Z. ^[3]; Schlottmann, P. ^[4]; Pagliuso, P. G. ^[1]; Urbano, R. R. ^[1]; Rettori, C. ^[5]

---

1. Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, SP 13083-859, Brazil
2. Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
3. Department of Physics and Astronomy, University of California Irvine, Irvine, California 92697, USA
4. Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
5. Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, SP 13083-859, Brazil, Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, SP 09210-170, Brazil

We report X-band Electron Spin Resonance (ESR) experiments on ≈ 0.2% and ≈ 0.7 % Er³⁺ doped SmB₆ at low temperature (4 K - 40 K). The crystal field ground state of Er³⁺ in SmB₆ is a Γ₈ quartet with a nearby Γ₆ excited doublet. The angular dependence of the resonances is not consistent with transitions between pure cubic crystal field states. The data were interpreted in terms of a dynamic Jahn-Teller (JT) effect by a coupling to Γ₃ vibrational modes, which we propose to originate from the rattling of the small Er³⁺ ions in the large SmB6 cage. Our data show an anisotropic pair of E and E’ resonances at g ≈ 4.4 and two nearly isotropic signals at g ≈ 5.8, one intense and narrow (A vibrational mode) and the other broad and faint, which we attribute to Er³⁺ ions at lattice sites which are strongly affected by strain, defects and/or extrinsic Al impurities that inhibits the JT effects. Our results are in general consistent with those previously reported by Sturm et al. In addition to the angular dependence of the lines, we discuss the intensities, g-values and the linewidths of the Er³⁺ transitions as a function of temperature.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC52-06NA25396
• OSTI ID: 1349331
• Alternate ID(s): OSTI ID: 1375881; OSTI ID: 1421272
• Report Number(s): LA-UR-17-23578; AAIDBI; 10.1063/1.4974914
• Journal Information: AIP Advances, Journal Name: AIP Advances Vol. 7 Journal Issue: 5; ISSN 2158-3226
• Publisher: American Institute of Physics
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
Material Science