Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 25: Superconductivity: Cuprate High-Temperature Superconductors 1

TT 25.3: Vortrag

Mittwoch, 25. März 2009, 10:00–10:15, HSZ 304

Renormalization of the longitudinal bond-stretching phonon branch in La_1.95Sr_0.05CuO₄ probed by inelastic neutron scattering technique — •A. Hamann¹, D. Lamago^1,2, L. Pintschovius¹, K. Yamada³, M. Fujita³, and D. Reznik^1,2 — ¹Institut für Festkörperphysik, KIT, 76021 Karlsruhe, Germany — ²LLB, CEA Saclay, 99191 Gif sur Yvette, France — ³Institute for Materials Research, Tohoku Univ., Katahira, Sendai 980-8577, Japan

La_2−xSr_xCuO₄ becomes superconducting (sc) for 0.06 ≤ x < 0.3, where optimal doping of x = 0.15 results in T_c up to 38 K. The mechanism leading to SC remains to be understood. Neutron scattering experiments revealed anomalous phonon behavior that hints at an enhanced electron-phonon coupling possibly connected to dynamic stripe order [1].

We report our latest measurements on non-sc La_1.95Sr_0.05CuO₄. Shell model predictions including resolution effects were used to fit the data. We found that in comparison to the sc-samples the anomalous phonon behavior becomes much less pronounced.

[1] D. Reznik et al., Nature 440, 1170 (2006)