Article

# Doping dependence of density response and bond-stretching phonons in cuprates

Physica B Condensed Matter (Impact Factor: 1.28). 01/2005; 359-361:620-622. DOI: 10.1016/j.physb.2005.01.170

Source: arXiv

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**ABSTRACT:**On the basis of a semiphenomenological model, it is argued that the anomalous properties of the bond-stretching (BS) in-plane phonon modes in cuprate superconductors and some other metallic perovskite oxides are due to coupling to the mid-infrared structure in the electronic charge fluctuation spectrum. The energy scale of this charge mode is several times larger than the phonon frequency, i.e., within 0.2–0.6 eV, and its doping and momentum dependence is discussed in relation to experimentally observed behavior of the BS phonons. Experiments on the effect of oxygen isotope substitution on the phonon softening and linewidth are suggested as a source of important information on the charge excitations, and equations describing isotope effects are derived. The set of equations is overcomplete and can therefore serve as a consistency test for the model. We discuss how the midinfrared scenario could offer an explanation of anomalous BS phonon observed in different perovskites in a unified framework.Physical Review B 01/2007; 75(1). · 3.66 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**We examine the single-particle excitation spectrum in the one-dimensional Hubbard-Holstein model at half-filling by performing the dynamical density matrix renormalization group (DDMRG) calculation. The DDMRG results are interpreted as superposition of spectra for a spinless carrier dressed with phonons. The superposition is a consequence of robustness of the spin-charge separation against electron-phonon coupling. The separation is in contrast to the coupling between phonon and spin degrees of freedom in two-dimensional systems. We discuss implication of the results of the recent angle-resolved photoemission spectroscopy measurements on SrCuO${}_{2}$. Comment: 5 pages, 4 figures. submitted to the Physical Review LettersPhysical review. B, Condensed matter 11/2005; · 3.77 Impact Factor -
##### Article: Polaron signatures in the phonon dispersion of high-temperature superconducting copper oxides

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**ABSTRACT:**High-temperature superconducting copper oxides display a variety of both long-range and local lattice anomalies which are related to the onset of the pseudogap phase and / or the onset of superconductivity. Here we show that these anomalies demonstrate polaron formation where specifically the local character of the polarons plays an important role. We predict that unconventional isotope effects will appear in both the long-wavelength and local lattice effects.EPL (Europhysics Letters) 03/2013; 101(4):47004. · 2.26 Impact Factor

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