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Title: Electron-lattice interactions strongly renormalize the charge-transfer energy in the spin-chain cuprate Li2CuO2

Strongly correlated insulators are broadly divided into two classes: Mott–Hubbard insulators, where the insulating gap is driven by the Coulomb repulsion U on the transition-metal cation, and charge-transfer insulators, where the gap is driven by the charge-transfer energy Δ between the cation and the ligand anions. The relative magnitudes of U and Δ determine which class a material belongs to, and subsequently the nature of its low-energy excitations. These energy scales are typically understood through the local chemistry of the active ions. Here we show that the situation is more complex in the low-dimensional charge-transfer insulator Li2CuO2, where Δ has a large non-electronic component. Combining resonant inelastic X-ray scattering with detailed modelling, we determine how the elementary lattice, charge, spin and orbital excitations are entangled in this material. This results in a large lattice-driven renormalization of Δ, which significantly reshapes the fundamental electronic properties of Li2CuO2.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5] ;  [6] ;  [7] ;  [5] ;  [5] ;  [6] ;  [8]
  1. Univ. of Tennessee, Knoxville, TN (United States)
  2. Paul Scherrer Inst. (PSI), Villigen (Switzerland); Univ. of Zurich (Switzerland)
  3. Leibniz Inst. for Solid State and Materials Research (IFW), Dresden (Germany); Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
  4. Paul Scherrer Inst. (PSI), Villigen (Switzerland); Science and Technology Facilities Council (STFC), Harwell Campus, Oxford (United Kingdom). Diamond Light Source, Ltd.
  5. Leibniz Inst. for Solid State and Materials Research (IFW), Dresden (Germany)
  6. Paul Scherrer Inst. (PSI), Villigen (Switzerland)
  7. Academy of Sciences of the Czech Republic (ASCR), Prague (Czech Republic). Inst. of Physics
  8. Leibniz Inst. for Solid State and Materials Research (IFW), Dresden (Germany); Dresden Univ. of Technology (Germany)
Publication Date:
OSTI Identifier:
1258649
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE