Evidence for a charge collective mode associated with superconductivity in copper oxides from neutron and x-ray scattering measurements of la 2 - X Sr x CuO 4

S. R. Park, T. Fukuda, A. Hamann, D. Lamago, L. Pintschovius, M. Fujita, K. Yamada, D. Reznik

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

In superconducting copper oxides, some Cu-O bond-stretching phonons around 70 meV show anomalous giant softening and broadening of electronic origin, and electronic dispersions have large renormalization kinks near the same energy. These observations suggest that phonon broadening originates from quasiparticle excitations across the Fermi surface and the electronic dispersion kinks originate from coupling to anomalous phonons. We measured the phonon anomaly in underdoped (x=0.05) and overdoped (x=0.20 and 0.25) La2-xSrxCuO4 by inelastic neutron and x-ray scattering with high resolution. Combining these and previously published data, we found that doping dependence of the magnitude of the giant phonon anomaly is very different from that of the ARPES kink, i.e., the two phenomena are not connected. We show that these results provide indirect evidence that the phonon anomaly originates from novel collective charge excitations as opposed to interactions with electron-hole pairs. Their amplitude follows the superconducting dome so these charge modes may be important for superconductivity.

Original languageEnglish
Article number020506
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume89
Issue number2
DOIs
Publication statusPublished - 2014 Jan 21

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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