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This content will become publicly available on October 23, 2018

Title: Fermi surface in the absence of a Fermi liquid in the Kondo insulator SmB 6

The search for a Fermi surface in the absence of a conventional Fermi liquid has thus far yielded very few potential candidates. Among promising materials are spin-frustrated Mott insulators near the insulator–metal transition, where theory predicts a Fermi surface associated with neutral low-energy excitations. In this paper, we reveal another route to experimentally realize a Fermi surface in the absence of a Fermi liquid by the experimental study of a Kondo insulator SmB 6 positioned close to the insulator–metal transition. We present experimental signatures down to low temperatures (<<1 K) associated with a Fermi surface in the bulk, including a sizeable linear specific heat coefficient, and on the application of a finite magnetic field, bulk magnetic quantum oscillations, finite quantum oscillatory entropy, and substantial enhancement in thermal conductivity well below the charge gap energy scale. Finally, the weight of evidence indicates that despite an extreme instance of Fermi liquid breakdown in Kondo insulating SmB 6, a Fermi surface arises from novel itinerant low-energy excitations that couple to magnetic fields, but not weak DC electric fields.
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  1. Univ. of Cambridge (United Kingdom). Cavendish Lab.
  2. Univ. of Waterloo, ON (Canada). Dept. of Physics and Astronomy
  3. National High Magnetic Field Lab. (MagLab), Tallahassee, FL (United States)
  4. Univ. of Warwick, Coventry (United Kingdom). Dept. of Physics
  5. Univ. of Tokyo, Kashiwa (Japan). Inst. for Solid State Physics
  6. Univ. of Florida, Gainesville, FL (United States). Dept. of Physics
  7. Univ. of Cambridge (United Kingdom). Cavendish Lab.; Univ. of Oxford (United Kingdom). Dept. of Physics
  8. Univ. of Cambridge (United Kingdom). Cavendish Lab.; Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Physics
  9. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  10. Osaka Univ., Toyonaka (Japan). Dept. of Chemistry
  11. National Academy of Sciences of Ukraine, Kiev (Ukraine)
Publication Date:
Report Number(s):
Journal ID: ISSN 1745-2473
Grant/Contract Number:
AC52-06NA25396; SC0002613; DMR-1157490; EP/P024947/1; EP/M028771/1; EP/K012894/1; EP/L014963/1; 337425; 15H05883; 15H03682; JP16K05447
Accepted Manuscript
Journal Name:
Nature Physics
Additional Journal Information:
Journal Volume: 14; Journal Issue: 2; Journal ID: ISSN 1745-2473
Nature Publishing Group (NPG)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); National High Magnetic Field Lab. (MagLab), Tallahassee, FL (United States); Univ. of Cambridge (United Kingdom); Univ. of Warwick, Coventry (United Kingdom); Univ. of Waterloo, ON (Canada); Univ. of Tokyo, Kashiwa (Japan); Osaka Univ., Toyonaka (Japan)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); Royal Society (United Kingdom); Engineering and Physical Sciences Research Council (EPSRC); European Research Council (ERC); Leverhulme Trust (United Kingdom); Natural Sciences and Engineering Research Council of Canada (NSERC); Ministry of Education, Culture, Sports, Science and Technology (MEXT) (Japan)
Country of Publication:
United States
OSTI Identifier: