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Title: Anharmonic rattling vibrations effects in the ESR of Er 3+ doped SmB 6 Kondo insulator

We report X-band Electron Spin Resonance (ESR) experiments on ≈ 0.2% and ≈ 0.7 % Er 3+ doped SmB 6 at low temperature (4 K - 40 K). The crystal field ground state of Er 3+ in SmB 6 is a Γ 8 quartet with a nearby Γ 6 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 Γ 3 vibrational modes, which we propose to originate from the rattling of the small Er 3+ 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 Er 3+ 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 themore » linewidths of the Er 3+ transitions as a function of temperature.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [1] ;  [5]
  1. Univ. Estadual de Campinas, Campinas (Brazil)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Univ. of California, Irvine, CA (United States)
  4. Florida State Univ., Tallahassee, FL (United States)
  5. Univ. Estadual de Campinas, Campinas (Brazil); Univ. Federal do ABC, Santo André (Brazil)
Publication Date:
Report Number(s):
LA-UR-17-23578
Journal ID: ISSN 2158-3226; AAIDBI
Grant/Contract Number:
AC52-06NA25396
Type:
Published Article
Journal Name:
AIP Advances
Additional Journal Information:
Journal Volume: 7; Journal Issue: 5; Journal ID: ISSN 2158-3226
Publisher:
American Institute of Physics (AIP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Material Science
OSTI Identifier:
1349331
Alternate Identifier(s):
OSTI ID: 1375881; OSTI ID: 1421272