Dresden 2009 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 25: Superconductivity: Cuprate High-Temperature Superconductors 1

TT 25.4: Talk

Wednesday, March 25, 2009, 10:15–10:30, HSZ 304

Charge stripes and electron phonon coupling in cuprates — •A. C. Komarek¹, A. Hiess², H. Hiraka³, K. Ikeuchi³, M. v. Zimmermann⁴, M. Fujita³, K. Yamada³, and M. Braden¹ — ¹II. Physikalisches Institut, Universität zu Köln, Zülpcher Str. 77, 50937 Köln, Germany — ²Institut Laue-Langevin, BP 156, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9, France — ³Institute for Material Research, Tohoku University, Katahira, Sendai 980-8577, Japan — ⁴Hamburger Synchrotronstrahlungslabor HASYLAB at Deutsches Elektronen-Synchrotron, 22603 Hamburg, Germany

The role of electron-phonon coupling and its relevance to the pairing meachanism in high-temperature superconductivity is still a matter of controversy. The (La,Sr)₂CuO₄ (LSCO) system appears well suited for a study of the electron phonon coupling as the lattice dynamics is less complex than that of other cuprates. The strongest signatures of electron-phonon coupling are found in the longitudinal bond-stretching branches. In general these modes couple to charge fluctuations on the metal sites. In particular, the polarization patterns of modes propagating along the [100]-direction correspond to the distortions expected for the stripe ordering, which occurs in Nd-codoped LSCO and in La_1.88Ba_0.12CuO₄. We have searched for charge stripe order and studied the electron phonon coupling in the spin glass phase of LSCO (x = 0.05). Furthermore, the response of the electron phonon anomaly in LSCO (x ≈ 0.12) on Zn- and Ni-doping was analysed.