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High-energy magnetic excitations from heavy quasiparticles in CeCu2Si2.


ABSTRACT: Magnetic fluctuations is the leading candidate for pairing in cuprate, iron-based, and heavy fermion superconductors. This view is challenged by the recent discovery of nodeless superconductivity in CeCu2Si2, and calls for a detailed understanding of the corresponding magnetic fluctuations. Here, we mapped out the magnetic excitations in superconducting (S-type) CeCu2Si2 using inelastic neutron scattering, finding a strongly asymmetric dispersion for E≲1.5meV, which at higher energies evolves into broad columnar magnetic excitations that extend to E≳5meV. While low-energy magnetic excitations exhibit marked three-dimensional characteristics, the high-energy magnetic excitations in CeCu2Si2 are almost two-dimensional, reminiscent of paramagnons found in cuprate and iron-based superconductors. By comparing our experimental findings with calculations in the random-phase approximation,we find that the magnetic excitations in CeCu2Si2 arise from quasiparticles associated with its heavy electron band, which are also responsible for superconductivity. Our results provide a basis for understanding magnetism and superconductivity in CeCu2Si2, and demonstrate the utility of neutron scattering in probing band renormalization in heavy fermion metals.

SUBMITTER: Song Y 

PROVIDER: S-EPMC10644953 | biostudies-literature | 2021

REPOSITORIES: biostudies-literature

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High-energy magnetic excitations from heavy quasiparticles in CeCu2Si2.

Song Yu Y   Wang Weiyi W   Cao Chongde C   Yamani Zahra Z   Xu Yuanji Y   Sheng Yutao Y   Löser Wolfgang W   Qiu Yiming Y   Yang Yi-Feng YF   Birgeneau Robert J RJ   Dai Pengcheng P  

NPJ quantum information 20210101


Magnetic fluctuations is the leading candidate for pairing in cuprate, iron-based, and heavy fermion superconductors. This view is challenged by the recent discovery of nodeless superconductivity in CeCu2Si2, and calls for a detailed understanding of the corresponding magnetic fluctuations. Here, we mapped out the magnetic excitations in superconducting (S-type) CeCu2Si2 using inelastic neutron scattering, finding a strongly asymmetric dispersion for E≲1.5meV, which at higher energies evolves in  ...[more]

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