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Title: Effects of spin excitons on the surface states of SmB 6 : A photoemission study

We present the results of a high-resolution valence-band photoemission spectroscopic study of SmB 6 which shows evidence for a V-shaped density of states of surface origin within the bulk gap. The spectroscopy data are interpreted in terms of the existence of heavy 4 f surface states, which may be useful in resolving the controversy concerning the disparate surface Fermi-surface velocities observed in experiments. Most importantly, we find that the temperature dependence of the valence-band spectrum indicates that a small feature appears at a binding energy of about - 9 meV at low temperatures. We also attribute this feature to a resonance caused by the spin-exciton scattering in SmB 6 which destroys the protection of surface states due to time-reversal invariance and spin-momentum locking. Thus, the existence of a low-energy spin exciton may be responsible for the scattering, which suppresses the formation of coherent surface quasiparticles and the appearance of the saturation of the resistivity to temperatures much lower than the coherence temperature associated with the opening of the bulk gap.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [2] ;  [4] ;  [4] ;  [5] ;  [6] ;  [1]
  1. Temple Univ., Philadelphia, PA (United States). Dept. of Physics, Temple Materials Inst.
  2. Julich Research Center (Germany). Peter Grunberg Inst.
  3. Helmholtz-Zentrum Berlin for Materials and Energy, GmbH (Germany); Leibniz Institute for Solid State and Material Research (IFW), Dresden (Germany)
  4. Univ. of California, Irvine, CA (United States). Dept. of Physics and Astronomy
  5. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  6. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Maria Curie-Sklodowska Univ., Lublin (Poland). Inst. of Physics
Publication Date:
Report Number(s):
LA-UR-17-23577
Journal ID: ISSN 2469-9950; PRBMDO; TRN: US1702710
Grant/Contract Number:
AC52-06NA25396; W911NF-15-1-0181; FG02-01Er45872; FG02-01ER45872
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal Issue: 23; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Material Science
OSTI Identifier:
1392879
Alternate Identifier(s):
OSTI ID: 1335190

Arab, Arian, Gray, A. X., Nemšák, S., Evtushinsky, D. V., Schneider, C. M., Kim, Dae-Jeong, Fisk, Zachary, Rosa, P. F. S., Durakiewicz, T., and Riseborough, P. S.. Effects of spin excitons on the surface states of SmB6 : A photoemission study. United States: N. p., Web. doi:10.1103/PhysRevB.94.235125.
Arab, Arian, Gray, A. X., Nemšák, S., Evtushinsky, D. V., Schneider, C. M., Kim, Dae-Jeong, Fisk, Zachary, Rosa, P. F. S., Durakiewicz, T., & Riseborough, P. S.. Effects of spin excitons on the surface states of SmB6 : A photoemission study. United States. doi:10.1103/PhysRevB.94.235125.
Arab, Arian, Gray, A. X., Nemšák, S., Evtushinsky, D. V., Schneider, C. M., Kim, Dae-Jeong, Fisk, Zachary, Rosa, P. F. S., Durakiewicz, T., and Riseborough, P. S.. 2016. "Effects of spin excitons on the surface states of SmB6 : A photoemission study". United States. doi:10.1103/PhysRevB.94.235125. https://www.osti.gov/servlets/purl/1392879.
@article{osti_1392879,
title = {Effects of spin excitons on the surface states of SmB6 : A photoemission study},
author = {Arab, Arian and Gray, A. X. and Nemšák, S. and Evtushinsky, D. V. and Schneider, C. M. and Kim, Dae-Jeong and Fisk, Zachary and Rosa, P. F. S. and Durakiewicz, T. and Riseborough, P. S.},
abstractNote = {We present the results of a high-resolution valence-band photoemission spectroscopic study of SmB 6 which shows evidence for a V-shaped density of states of surface origin within the bulk gap. The spectroscopy data are interpreted in terms of the existence of heavy 4 f surface states, which may be useful in resolving the controversy concerning the disparate surface Fermi-surface velocities observed in experiments. Most importantly, we find that the temperature dependence of the valence-band spectrum indicates that a small feature appears at a binding energy of about - 9 meV at low temperatures. We also attribute this feature to a resonance caused by the spin-exciton scattering in SmB 6 which destroys the protection of surface states due to time-reversal invariance and spin-momentum locking. Thus, the existence of a low-energy spin exciton may be responsible for the scattering, which suppresses the formation of coherent surface quasiparticles and the appearance of the saturation of the resistivity to temperatures much lower than the coherence temperature associated with the opening of the bulk gap.},
doi = {10.1103/PhysRevB.94.235125},
journal = {Physical Review B},
number = 23,
volume = 94,
place = {United States},
year = {2016},
month = {12}
}