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Title: Nematic fluctuations and phase transitions in LaFeAsO: A Raman scattering study

Raman scattering experiments on LaFeAsO with distinct antiferromagnetic ( T AFM=140 K) and tetragonal-orthorhombic ( T S=155 K) transitions show a quasielastic peak (QEP) in B 2g symmetry (2 Fe tetragonal cell) that fades away below ~ T AFM and is ascribed to electronic nematic fluctuations. A scaling of the reported shear modulus with the T dependence of the QEP height rather than the QEP area indicates that magnetic degrees of freedom drive the structural transition. As a result, the large separation between T S and T AFM in LaFeAsO compared to BaFe 2As 2 manifests itself in slower dynamics of nematic fluctuations in the former.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1] ;  [5] ;  [1]
  1. Univ. of Campinas-UNICAMP, Sao Paulo (Brazil)
  2. Univ. of Campinas-UNICAMP, Sao Paulo (Brazil); Federal Univ. of Goias-UFG, Goias (Brazil)
  3. Federal Univ. of ABC-UFABC, Sao Paulo (Brazil)
  4. Ames Lab., Ames, IA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  5. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
Publication Date:
Report Number(s):
IS-J-9405
Journal ID: ISSN 2469-9950; PRBMDO; TRN: US1702793
Grant/Contract Number:
2012/04870-7; AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 96; Journal Issue: 1; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Ames Lab., Ames, IA (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
OSTI Identifier:
1374745
Alternate Identifier(s):
OSTI ID: 1369090