A microscopic modeling of phonon dynamics and charge response in NdCuO

Abstract

A description of phonon dynamics and charge response of the $n$-doped high-temperature superconductor (HTSC) NdCuO is presented based upon a microscopic modeling of the electronic density response. This is accomplished starting from the insulating state via the underdoped strange metallic to the more conventional metallic state by consecutive orbital selective incompressibility-compressibility transitions in terms of strict sum rules for the charge response. The approach proposed in this work for the $n$-doped HTSC's modifies the modeling recently applied to the $p$-doped compounds and expresses an electron-hole asymmetry introduced by doping. A qualitative physical picture consistent with our modeling of the electronic state in the cuprates is given in which a sufficiently broad set of orbital degrees of freedom, i.e. Cu3d/$4s$ and O$2p$ is essential. Within the framework of linear response theory we calculate full phonon dispersion curves in the different phases. In particular, the strongly doping dependent anomalous high-frequency oxygen bond-stretching modes (OBSM) found experimentally in the $p$-doped HTSC's and also recently for $n$-doped Nd${}_{1.85}$Ce${}_{0.15}$CuO${}_4$ are investigated and compared with experimental results from inelastic neutron scattering and inelastic x-ray scattering, respectively. We calculate an anticrossing scenario for the OBSM in $n$-doped NdCuO which is absent in the case of $p$-doped LaCuO and relate it to the different crystal structure. Phonon-induced electronic charge redistributions of the anomalous OBSM due to nonlocal electron-phonon interaction effects of charge-fluctuation type giving reason to dynamic stripes are also studied.

A discussion is added of the relation of the pseudogap and the superdonducting gap. 2 new references

References in corpus (7)

• Quantum oscillations and the Fermi surface in an underdoped high-Tc superconductor
• Electron pockets in the Fermi surface of hole-doped high-Tc superconductors
• Interplay of electron-lattice interactions and superconductivity in Bi2Sr2CaCu2O8+d
• Oxygen phonon branches in overdoped La${}_{1.7}$Sr${}_{0.3}$CuO${}_4$
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• Precise determination of the superconducting gap along the diagonal direction of Bi2Sr2CaCu2O8+y: Evidence for extended s-wave gap symmetry

Cited by in corpus (2)

• The impact of dynamical screening on the phonon dynamics of LaCuO
• Microscopic calculation of the phonon dynamics of Sr${}_2$RuO${}_4$ compared with La${}_2$CuO${}_4$