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TT: Fachverband Tiefe Temperaturen

TT 2: SC: Properties, Electronic Structure, Mechanisms 1

TT 2.6: Talk

Monday, March 14, 2011, 12:00–12:15, HSZ 301

Charge stripe order near the surface of 12-percent doped La_2−xSr_xCuO₄ — •M. Buchholz¹, H.-H. Wu^1,2, C. Trabant^1,4, C.-F. Chang¹, A. Komarek¹, F. Heigl³, E. Schierle⁴, M. v. Zimmermann⁵, M. Cwik¹, F. Nakamura⁶, L. H. Tjeng⁷, M. Braden¹, and C. Schüßler-Langeheine^1,4 — ¹II. Physikalisches Institut, Universität zu Köln — ²NSRRC, Hsinchu, Taiwan — ³ALBA, Barcelona, Spain — ⁴Helmholtz-Zentrum Berlin — ⁵DESY, Hamburg — ⁶ADSM, Hiroshima University, Japan — ⁷MPI CPfS, Dresden

Stripe-like spin and charge order has been observed in many layered cuprate, nickelate and cobaltate systems by neutron or x-ray diffraction. For the prototypical high-temperature superconductor La_2−xSr_xCuO₄ (LSCO) no charge-stripe signal has been found so far, but there are several indications for a proximity to the formation of charge stripes. We found a pronounced charge-stripe signal in the near surface region of 12-percent doped LSCO, but no such signal from the bulk. We conclude that this compound is so close to the formation of charge stripes that small perturbations near the surface can stabilize this order. Our finding of different phases in the bulk and near the surface of LSCO has to be taken into account for the interpretation of data from surface-sensitive probes like photoelectron spectroscopy or scanning tunnelling spectroscopy.