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Title: Magnetic field tuning of an excitonic insulator between the weak and strong coupling regimes in quantum limit graphite [Tunable excitonic insulator in quantum limit graphite]

Here, the excitonic insulator phase has long been predicted to form in proximity to a band gap opening in the underlying band structure. The character of the pairing is conjectured to crossover from weak (BCS-like) to strong coupling (BEC-like) as the underlying band structure is tuned from the metallic to the insulating side of the gap opening. Here we report the high-magnetic field phase diagram of graphite to exhibit just such a crossover. By way of comprehensive angle-resolved magnetoresistance measurements, we demonstrate that the underlying band gap opening occurs inside the magnetic field-induced phase, paving the way for a systematic study of the BCS-BEC-like crossover by means of conventional condensed matter probes.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [2] ; ORCiD logo [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Huazhong Univ. of Science and Technology, Wuhan (China)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Florida State Univ., Tallahassee, FL (United States)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Cornell Univ., Ithaca, NY (United States)
  5. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Max Planck Institute for Chemical Physics of Solids, Presden (Germany)
Publication Date:
Report Number(s):
LA-UR-14-29680; LA-UR-17-30078
Journal ID: ISSN 2045-2322
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 36 MATERIALS SCIENCE; High Magnetic Field Science
OSTI Identifier:
1375160
Alternate Identifier(s):
OSTI ID: 1409794