Berlin 2012 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 45: Correlated Electrons: Poster Session

TT 45.79: Poster

Donnerstag, 29. März 2012, 15:00–19:00, Poster B

Orbitons and bi-orbitons in GdVO₃ and YVO₃ — •Luis Fels¹, Michael Voigt¹, Komalavalli Thirunavukkuarasu¹, Eva Benckiser^2,1, Giacomo Ghiringhelli³, Marco Moretti Sala³, Graeme R. Blake⁴, Nandang Mufti⁴, Agung A. Nugroho^4,5, 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 — ⁶IFWDresden — ⁷Paul Scherrer Institut, Villigen

Here we report on optical measurements and high-resolution RIXS on GdVO₃ and YVO₃ single crystals. The goal of the measurements is the observation of so called orbitons which are, in analogy to magnons, collective orbital excitations on top of an orbitally ordered state. In both investigated compounds a G-type orbital ordered (OO) phase occurs, but only in YVO₃ an additional low temperature phase with C-type OO exists.

In the optical conductivity σ(w) of GdVO₃, a striking feature is seen at 0.4 eV in the OO phase which is interpreted as bi-orbiton in agreement with further investigations on YVO₃ and HoVO₃ [1]. With the RIXS measurements it was possible to observe a significant dispersion of the intra-t_2g excitations at roughly 0.2 eV. However, the origin of this dispersion, whether it is due to a collective character of the excitations or a local effect, is still unclear.
E. Benckiser et al., New J. Phys. 10, 053027 (2008).