Post-growth annealing effects on charge and spin excitations in Nd2−xCexCuO4
| Autor: | Jun'ichiro Mizuki, Biqiong Yu, Masumi Ashida, Masaki Fujita, Shun Asano, Jun Okamoto, Kenji Ishii, Martin Greven, Di Jing Huang |
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| Rok vydání: | 2021 |
| Předmět: |
Superconductivity
Materials science Physics and Astronomy (miscellaneous) Condensed matter physics Scattering Order (ring theory) Charge (physics) 02 engineering and technology Electron Neutron scattering 021001 nanoscience & nanotechnology 01 natural sciences Condensed Matter::Superconductivity 0103 physical sciences Antiferromagnetism Condensed Matter::Strongly Correlated Electrons General Materials Science 010306 general physics 0210 nano-technology Spin (physics) |
| Zdroj: | Physical Review Materials. 5 |
| ISSN: | 2475-9953 |
| Popis: | We report a Cu $K$- and ${L}_{3}$-edge resonant inelastic x-ray scattering study of charge and spin excitations of bulk ${\mathrm{Nd}}_{2\ensuremath{-}x}{\mathrm{Ce}}_{x}{\mathrm{CuO}}_{4}$, with a focus on post-growth annealing effects. For the parent compound ${\mathrm{Nd}}_{2}{\mathrm{CuO}}_{4}$ $(x=0)$, a clear charge-transfer gap is observed in the as-grown state, whereas the charge excitation spectra indicate that electrons are doped in the annealed state. This is consistent with the observation that annealed thin-film and polycrystalline samples of $R{E}_{2}{\mathrm{CuO}}_{4}$ $(\mathrm{RE}=\text{rare earth})$ can become metallic and superconducting at sufficiently high electron concentrations without Ce doping. For $x=0.16$, a Ce concentration for which it is known that oxygen reduction destroys long-range antiferromagnetic order and induces superconductivity, we find that the high-energy spin excitations of non-superconducting as-grown and superconducting annealed crystals are nearly identical. This finding is in stark contrast to the significant changes in the low-energy spin excitations previously observed via neutron scattering. |
| Databáze: | OpenAIRE |
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