Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 33: Postersession Correlated Electrons: Metal Insulator Transition, Spin Systems and Itinerant Magnets

TT 33.4: Poster

Mittwoch, 25. März 2009, 14:00–18:00, P1A

Orbital and charge ordering in CuI₂S₄ thiospinel studied by Raman scattering — •Vladimir Gnezdilov^1,2, Peter Lemmens², Yurii Pashkevich³, Kwang-Yong Choi⁴, and Vladimir Tsurkan⁵ — ¹ILTP, Kharkov, Ukraine — ²IPKM, TU Braunschweig, Germany — ³Donetsk Phystech, Ukraine — ⁴Chung-Ang Univ., Seoul, Korea — ⁵IAP, Chisinau, Moldova

CuI₂S₄ displays a metal-insulator (MI) transition at 230 K with an abrupt decrease of the electrical conductivity and a loss of localized magnetic moments [1]. Below T_MI CuI₂S₄ undergoes a simultaneous charge ordering and spin-dimerization transition [2] – a rare phenomenon in three-dimensional compounds. Here we present a Raman scattering study of CuI₂S₄ through the MI transition showing drastic changes of the spectra below T_MI consistent with the formation of isotropic Ir³⁺ and Ir⁴⁺ octamers and spin dimerization [2].

[1] T. Furubayashi et al., J. Phys. Soc. Jpn. 63, 3333 (1994).

[2] P.G. Radaelli et al., Nature 416, 155 (2002).