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Title: Quasi-two-dimensional spin and phonon excitations in La1.965Ba0.035CuO4

Here, we present time-of-fight inelastic neutron scattering measurements of La1.965Ba0.035CuO4 (LBCO), a lightly doped member of the high temperature superconducting La-based cuprate family. By using time-of-flight neutron instrumentation coupled with single crystal sample rotation we obtain a four-dimensional data set (three Q and one energy) that is both comprehensive and spans a large region of reciprocal space. Our measurements identify rich structure in the energy dependence of the highly dispersive spin excitations, which are centered at equivalent (1/2, 1/2, L) wave-vectors. These structures correlate strongly with several crossings of the spin excitations with the lightly dispersive phonons found in this system. These eects are signicant and account for on the order of 25% of the total inelastic scattering for energies between ≈5 and 40meV at low |Q|. Interestingly, this scattering also presents little or no L-dependence. As the phonons and dispersive spin excitations centred at equivalent (1/2, 1/2, L) wave-vectors are common to all members of La-based 214 copper oxides, we conclude such strong quasi-two dimensional scattering enhancements are likely to occur in all such 214 families of materials, including those concentrations corresponding to superconducting ground states. Such a phenomenon appears to be a fundamental characteristic of these materials andmore » is potentially related to superconducting pairing.« less
 [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [1] ;  [5]
  1. McMaster Univ., Hamilton, ON (Canada)
  2. National Institute of Standards and Technology, Gaithersburg, MD (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. National Institute of Standards and Technology, Gaithersburg, MD (United States); Univ. of Maryland, College Park, MD (United States)
  5. McMaster Univ., Hamilton, ON (Canada); Canadian Institute for Advanced Research, Toronto, ON (Canada)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 91; Journal Issue: 22; Journal ID: ISSN 1098-0121
American Physical Society (APS)
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States