Regensburg 2002 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 22: Postersitzung III: Syst. korr. Elektr.: Theorie II (1-15), Metall-Isol.- und Phasenüberg
änge (16-33), SL: Massivmat., Bandl., Pinning, Vortexdyn., Transport, Korngr. (34-43), Niedrigdim. Syst., Magnetotransport (44-63)

TT 22.32: Poster

Donnerstag, 14. März 2002, 14:00–17:30, A

Stripe conductivity in La_2−xSr_xNiO₄ obtained from electronic Raman scattering — •P. Lemmens^3,4, V. Gnezdilov¹, Yu. Pashkevich², K.-Y. Choi⁴, G. Güntherodt⁴, J.M. Tranquada⁵, D.J. Buttrey⁶, and K. Nakajima⁷ — ¹B.I. Verkin Inst. for Low Temp. Physics NASU, Kharkov, Ukraine — ²A.A.Galkin Donetsk Phystech NASU, Donetsk, Ukraine — ³IMNF, TU Braunschweig, Mendelsohnstr. 3, Braunschweig, Germany — ⁴2. Phys. Inst. RWTH Aachen, Aachen Germany — ⁵BNL, Upton, NY, USA — ⁶Univ. of Delaware, Newark, Delaware, USA — ⁷ISSP Tokyo, Tokai, Ibaraki, Japan

We report the results of electronic Raman scattering experiments on La_2−xSr_xNiO₄ with x = 1/3 and x=0.225 that exhibit commensurate and incommensurate charge-stripe order with one or less than 1 hole per Ni site along the stripe, respectively. Markedly different Raman response is observed in the B_2g symmetry component. A charge ordering induced shift of spectral weight and pseudo gap formation is investigated. It is used to pinpoint a remnant conductivity along the charge threads in the incommensurate stripe-ordered state.
We acknowledge support by DFG SPP1073, NATO and INTAS.