Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 41: CE: Spin Systems and Itinerant Magnets 1
TT 41.2: Vortrag
Mittwoch, 16. März 2011, 18:30–18:45, HSZ 105
Orbitons and bi-orbitons in GdVO3 and YVO3 observed by RIXS — •Luis Mäder1, Komalavalli Thirunavukkuarasu1, Eva Benckiser2,1, Giacomo Ghiringhelli3, Marco Moretti3, Graeme R. Blake4, Nandang Mufti4, A. Agung Nugroho4,5, Thomas T. M. Palstra4, Pasquale Marra6, Krzysztof Wohlfeld6, Jeroen van den Brink6, Maurits Haverkort2, Thorsten Schmitt7, and Markus Grüninger1 — 1Universität zu Köln — 2MPI-FKF Stuttgart — 3Politecnico di Milano — 4University of Groningen — 5Institut Teknologi Bandung — 6IFW Dresden — 7PSI Villigen
In an orbitally ordered state, exchange interactions between orbitals on neighbouring sites could give rise to a significant dispersion of the orbital excitations. These orbitons are analogous to spin waves. Here, we report on the observation of orbital excitations in YVO3 and GdVO3 by means of high-resolution RIXS across the V L3,2 and O K edges with the new SAXES beamline at the PSI, Villigen. Due to the excellent resolution of 60 meV, we are able to resolve the different intra-t2g excitations. Our data show 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]. For GdVO3 the one-orbiton energy shows a shift of up to 40 meV as a function of momentum. This shift could be related to dispersive orbitons or, alternatively, to two different intra-t2g excitations and a transfer of spectral weight between them. To figure this out we compare our data with recent calculations.
E. Benckiser et al., New J. Phys. 10, 053027 (2008).