Crystalline and magnetic structure of Ba2CuO3+delta investigated by x-ray absorption spectroscopy and resonant inelastic x-ray scattering

@article{ WOS:000620294800007,
Author = {Fumagalli, Roberto and Nag, Abhishek and Agrestini, Stefano and
   Garcia-Fernandez, Mirian and Walters, Andrew C. and Betto, Davide and
   Brookes, Nicholas B. and Braicovich, Lucio and Zhou, Ke-Jin and
   Ghiringhelli, Giacomo and Sala, Marco Moretti},
Title = {{Crystalline and magnetic structure of Ba2CuO3+delta investigated by
   x-ray absorption spectroscopy and resonant inelastic x-ray scattering}},
Journal = {{PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS}},
Year = {{2021}},
Volume = {{581}},
Month = {{FEB 15}},
Abstract = {{Motivated by the recent synthesis of Ba2CuO3+delta (BCO), a high
   temperature superconducting cuprate with putative d(3z2-r2) ground state
   symmetry, we investigated its electronic structure by means of Cu L-3
   x-ray absorption (XAS) and resonant inelastic x-ray scattering (RIXS) at
   the Cu L-3 edge on a polycrystalline sample. We show that the XAS
   profile of BCO is characterised by two peaks associated to inequivalent
   Cu sites, and that its RIXS response features a single, sharp peak
   associated to crystal-field excitations. We argue that these
   observations are only partially compatible with the previously proposed
   crystal structure of BCO. Based on our spectroscopic results and on
   previously published powder diffraction measurements, we propose a
   crystalline structure characterized by two inequivalent Cu sites located
   at alternated planes along the c axis: nominally trivalent Cu(1)
   belonging to very short Cu-O chains, and divalent Cu(2) in the oxygen
   deficient CuO1.5 planes. We also analyze the low-energy region of the
   RIXS spectra to estimate the magnitude of the magnetic interactions in
   BCO and find that in-plane nearest neighbor superexchange exceeds 120
   meV, similarly to that of other layered cuprates. Although these results
   do not support the pure d(3z2-r2) ground state scenario, they hint at a
   significant departure from the common quasi-2D electronic structure of
   superconducting cuprates of pure d(x2-y2) symmetry.}},
DOI = {{10.1016/j.physc.2020.1353810}},
Article-Number = {{1353810}},
ISSN = {{0921-4534}},
EISSN = {{1873-2143}},
ResearcherID-Numbers = {{Moretti, Marco/H-1034-2014}},
ORCID-Numbers = {{Garcia Fernandez, Mirian/0000-0002-6982-9066
   Nag, Abhishek/0000-0002-1394-5105
   Moretti, Marco/0000-0002-9744-9976}},
Unique-ID = {{WOS:000620294800007}},
}