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This content will become publicly available on September 15, 2015

Title: Spin-fluctuation-induced non-Fermi-liquid behavior with suppressed superconductivity in LiFe1-xCoxAs

A series of LiFe1–xCoxAs compounds with different Co concentrations by transport, optical spectroscopy, angle-resolved photoemission spectroscopy, and nuclear magnetic resonance. We observe a Fermi-liquid to non-Fermi-liquid to Fermi-liquid (FL-NFL-FL) crossover alongside a monotonic suppression of the superconductivity with increasing Co content. In parallel to the FL-NFL-FL crossover, we find that both the low-energy spin fluctuations and Fermi surface nesting are enhanced and then diminished, strongly suggesting that the NFL behavior in LiFe1–xCoxAs is induced by low-energy spin fluctuations that are very likely tuned by Fermi surface nesting. Our study reveals a unique phase diagram of LiFe1–xCoxAs where the region of NFL is moved to the boundary of the superconducting phase, implying that they are probably governed by different mechanisms.
Authors:
;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [2] ;  [4] ;  [5] ;  [5] ;  [2]
  1. Chinese Academy of Sciences (CAS), Beijing (China)
  2. Chinese Academy of Sciences (CAS), Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)
  3. Renmin Univ. of China, Beijing (China)
  4. Boston College, Chestnut Hill, MA (United States)
  5. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
OSTI Identifier:
1215773
Report Number(s):
BNL-111605-2015-JA
Journal ID: ISSN 2160-3308; PRXHAE; R&D Project: PO016; Kc0202020
Grant/Contract Number:
SC00112704; FG02-99ER45747; SC0012704
Type:
Published Article
Journal Name:
Physical Review. X
Additional Journal Information:
Journal Volume: 5; Journal Issue: 3; Journal ID: ISSN 2160-3308
Publisher:
American Physical Society
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (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; condensed matter physics; superconductivity