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Title: Origin of the charge gap in LaMnPO

In this paper, we present high temperature inelastic neutron scattering and magnetic susceptibility measurements of the antiferromagnetic insulator LaMnPO that are consistent with the presence of two-dimensional magnetic correlations up to a temperature Tmax≈700K»TN=375 K, the Néel temperature. Optical transmission measurements show the T=300 K direct charge gap Δ=1 eV has decreased only marginally by 500 K and suggest it decreases by only 10% at Tmax. Density functional theory and dynamical mean-field theory calculations reproduce a direct charge gap in paramagnetic LaMnPO only when a strong Hund's coupling JH=0.9 eV is included, as well as on-site Hubbard U=8 eV. In conclusion, our results show that LaMnPO is a Mott-Hund's insulator, in which the charge gap is rather insensitive to antiferromagnetic exchange coupling.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [1] ;  [1] ;  [5] ;  [5] ;  [6] ;  [6] ;  [2] ;  [3] ;  [7]
  1. Stony Brook Univ., NY (United States)
  2. Univ. of California, San Diego, CA (United States)
  3. Rutgers Univ., Piscataway, NJ (United States)
  4. Stony Brook Univ., NY (United States); Rutgers Univ., Piscataway, NJ (United States)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  6. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
  7. Stony Brook Univ., NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
OSTI Identifier:
1265254
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 90; Journal Issue: 18; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY