Dresden 2011 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 49: CE: Spin Systems and Itinerant Magnets 2

TT 49.16: Vortrag

Donnerstag, 17. März 2011, 18:15–18:30, HSZ 03

Probing the local magnetic structure of a quasi-1D cuprate with Resonant Inelastic X-Ray Scattering — •Claude Monney¹, Valentina Bisogni², Kejin Zhou¹, Roberto Kraus², Vladimir Strocov¹, Jochen Geck², and Thorsten Schmitt¹ — ¹Paul Scherrer Institut, Villigen PSI, Switzerland — ²IFW, Dresden, Germany

The quasi-one-dimensional cuprate Li₂CuO₂ is a prototype edge-sharing chain compound. The Cu²⁺ ions in this strongly correlated material give rise to one spin 1/2 per CuO₄ plaquette with a nearest neighbor Cu-O-Cu bond angle close to 90^∘ implying weak superexchange between Cu spins. As a result, spins order antiferromagnetically between the chains below T_N ∼ 9K, but ferromagnetically in the chains. We have performed Resonant Inelastic X-ray Scattering (RIXS) at Cu L₃ and O K-resonances at the ADRESS beamline of the Swiss Light Source on this compound. Our momentum resolved RIXS measurements at the Cu L₃-edge allow analyzing orbital excitations with high sensitivity. At the O K-edge, the RIXS spectra display a complicated interplay of low-energy excitations from charge, orbital and lattice degrees of freedom. In particular, we discuss charge transfer related spectral components in the scenario of exotic Zhang-Rice (ZR) singlet and triplet excitations which can be reached in the final state with O K-edge RIXS. The intensity of the ZR features can be related to the thermodynamics of domain walls in one dimension. This establishes RIXS as an excellent probe for investigating local magnetic order.