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Title: Strain-Driven Approach to Quantum Criticality in AFe 2As 2 with A=K, Rb, and Cs

The iron-based superconductors AFe 2As 2 with A = K, Rb, Cs exhibit large Sommerfeld coefficients approaching those of heavy-fermion systems. We have investigated the magnetostriction and thermal expansion of this series to shed light on this unusual behavior. Quantum oscillations of the magnetostriction allow identifying the band-specific quasiparticle masses which by far exceed the band-structure derived masses. The divergence of the Grüneisen ratio derived from thermal expansion indicates that with increasing volume along the series a quantum critical point is approached. In conclusion, the critical fluctuations responsible for the enhancement of the quasiparticle masses appear to weaken the superconducting state.
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3] ; ORCiD logo [4] ;  [5] ;  [6] ;  [7]
  1. Karlsruhe Inst. of Technology (KIT) (Germany). Inst. fur Technologie
  2. Karlsruher Institut fur Technologie, Germany
  3. Renmin Univ. of China, Beijing (China). Dept. of Physics
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  5. Rice Univ., Houston, TX (United States). Dept. of Physics and Astronomy
  6. Univ. of Tokyo (Japan). Dept. of Advanced Materials Science; Kyoto Univ. (Japan). Dept. of Physics
  7. Karlsruhe Inst. of Technology (KIT) (Germany). Inst. fur Technologie; Karlsruhe Inst. of Technology (KIT) (Germany). Physikalisches Inst.
Publication Date:
Report Number(s):
LA-UR-15-28161
Journal ID: ISSN 0031-9007
Grant/Contract Number:
AC52-06NA25396; 11374361; C-1411; PHY-1066293
Type:
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 116; Journal Issue: 23; Journal ID: ISSN 0031-9007
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); National Science Foundation (NSF); National Science Foundation of China
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Material Science
OSTI Identifier:
1414118
Alternate Identifier(s):
OSTI ID: 1256164