2 research outputs found
Determining the Electron-Phonon Coupling in Superconducting Cuprates by Resonant Inelastic X-ray Scattering: Methods and Results on NdBaCuO
The coupling between lattice vibration quanta and valence electrons can
induce charge density modulations and decisively influence the transport
properties of materials, e.g. leading to conventional superconductivity. In
high critical temperature superconductors, where electronic correlation is the
main actor, the actual role of electron-phonon coupling (EPC) is being
intensely debated theoretically and investigated experimentally. We present an
in-depth study of how the EPC strength can be obtained directly from resonant
inelastic x-ray scattering (RIXS) data through the theoretical approach derived
by Ament et al. [EPL 95, 27008 (2011)]. The role of the model parameters (e.g.
phonon energy , intermediate state lifetime , EPC matrix
element , and detuning energy ) is thoroughly analyzed, providing
general relations among them that can be used to make quantitative estimates of
the dimensionless EPC without detailed microscopic
modeling. We then apply these methods to very high resolution Cu edge
RIXS spectra of three NdBaCuO films. For the
insulating antiferromagnetic parent compound the value of as a function of
the in-plane momentum transfer is obtained for Cu-O bond-stretching (breathing)
and bond-bending (buckling) phonon branches. For the underdoped and the nearly
optimally doped samples, the effects of Coulomb screening and of
charge-density-wave correlations on are assessed. In light of the
anticipated further improvements of the RIXS experimental resolution, this work
provides a solid framework for an exhaustive investigation of the EPC in
cuprates and other quantum materials.Comment: 21 pages, 16 figure
Determining the electron-phonon coupling in superconducting cuprates by resonant inelastic x-ray scattering: Methods and results on Nd1+xBa2-xCu3O7-δ
The coupling between lattice vibration quanta and valence electrons can induce charge-density modulations and decisively influence the transport properties of materials, e.g., leading to conventional superconductivity. In high-critical-temperature superconductors, where electronic correlation is the main actor, the actual role of electron-phonon coupling (EPC) is being intensely debated theoretically and investigated experimentally. We present an in-depth study of how the EPC strength can be obtained directly from resonant inelastic x-ray scattering (RIXS) data through the theoretical approach derived by Ament et\ua0al. [Europhys. Lett. 95, 27008 (2011)]. The role of the model parameters (e.g., phonon energy ω0, intermediate state lifetime 1/Γ, EPC matrix element M, and detuning energy Ω) is thoroughly analyzed, providing general relations among them that can be used to make quantitative estimates of the dimensionless EPC g=(M/ω0)2 without detailed microscopic modeling. We then apply these methods to very high-resolution Cu L3-edge RIXS spectra of three Nd1+xBa2−xCu3O7−δ films. For the insulating antiferromagnetic parent compound, the value of M as a function of the in-plane momentum transfer is obtained for Cu-O bond-stretching (breathing) and bond-bending (buckling) phonon branches. For the underdoped and the nearly optimally doped samples, the effects of Coulomb screening and of charge-density-wave correlations on M are assessed. In light of the anticipated further improvements of the RIXS experimental resolution, this work provides a solid framework for an exhaustive investigation of the EPC in cuprates and other quantum materials