Dresden 2003 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 6: Postersitzung I (Amorphe- u. Tunnelsysteme, Niedrigdimensionale Systeme, Supraleitung: Elektronenstruktur, Phononen, Tunneln, Ordnungsparameter)

TT 6.21: Poster

Montag, 24. März 2003, 14:30–19:00, P2c, P2d

Magnon-Hole Scattering in Sr_14−xCa_xCu₂₄O₄₁ — •H. El Haes¹, C. Hess¹, B. Büchner¹, M. Hücker², U. Ammerahl², and A. Revcolevschi² — ¹II. Physikalisches Institut, RWTH Aachen — ²Laboratoire de Physico-Chimie, Universite Paris-Sud

We investigate the magnon thermal conductivity of the hole-doped spin ladders in Sr_14−xCa_xCu₂₄O₄₁ at low doping levels x. We calculate the magnon mean free path l_mag which is a local probe for the interaction of magnons with the doped holes in the ladders. A strong temperature- and doping dependence of magnon-hole scattering processes is present. In particular, theses processes freeze out below characteristic temperatures T that are equal to the critical temperatures of charge ordering that is observed in the ladders as well as in the chain structures. We conclude from our results a perfect charge order within the ladders with a correlation length larger than about 1000 lattice spacings. Alternative scenarios as a temperature driven charge transfer and electronic phase separation within the ladders are discussed.