Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 27: CE: Poster Session

TT 27.6: Poster

Mittwoch, 24. März 2010, 14:00–18:00, Poster D1

Orbitons and bi-orbitons in GdVO₃ and YVO₃ observed by RIXS — •Luis Mäder¹, Komalavalli Thirunavukkuarasu¹, Eva Benckiser^2,1, Giacomo Ghiringhelli³, Marco Moretti³, Graeme R. Blake⁴, Nandang Mufti⁴, Agung A. Nugroho^5,4, Thomas T. M. Palstra⁴, Maurits Haverkort², Thorsten Schmitt⁶, and Markus Grüninger¹ — ¹Universität zu Köln — ²MPI-FKF Stuttgart — ³Politecnico di Milano — ⁴University of Groningen — ⁵Institut Teknologi Bandung — ⁶PSI, Villigen

In an orbitally ordered state, one expects that exchange interactions between orbitals on neighbouring sites give rise to a novel kind of elementary excitations, so called orbitons, which are analogous to spin waves in a magnetically ordered state.

Here, we report on the observation of orbital excitations in YVO₃ and GdVO₃ by means of high-resolution resonant inelastic x-ray scattering (RIXS) across the V L_3,2 (V 2p → V 3d) and O K (O 1s → O 2p) edges with the new SAXES beamline at the PSI, Villigen.

Due to the excellent resolution of 60  meV, we are able to resolve two different features in the low energy regime. We interpret them as one- and bi-orbiton excitations in good agreement with our optical data [1]. We compare our data with results on YTiO₃ and LaTiO₃ by Ulrich et al. [2], who attribute the spectral weight at low energies mainly to bi-orbiton excitations.

[1] E. Benckiser et al., New J. Phys. 10, 053027 (2008).

[2] C. Ulrich et al., PRL 103, 107205 (2009).