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Dresden 2011 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 44: Poster Session Correlated Electrons

TT 44.75: Poster

Thursday, March 17, 2011, 10:00–13:00, P1

Collective orbital excitations in GdVO3 — •Michael Voigt1, Luis Mäder1, Konstantin Shportko1, Graeme R. Blake2, Nandang Mufti2, Agustinus A. Nugroho2,3, Thomas T. M. Palstra2, and Markus Grüninger11Universität zu Köln — 2University of Groningen — 3Institut Teknologi Bandung

In the vanadates (RVO3) orbital interactions are expected to be especially strong. In the compounds YVO3 and HoVO3 these interactions lead to two different phases of orbital ordering (OO), one in an intermediate temperature range with G-type OO and one low-temperature phase with C-type OO. [1] In these orbitally ordered states, one expects novel collective excitations, so called orbitons, which are analogous to spin waves in a magnetically ordered state.

Previous optical measurements of YVO3 and HoVO3 have shown a striking feature at 0.4 eV with polarization Ec in the intermediate phase which is interpreted as bi-orbiton excitation. [2] Furthermore a second interesting feature at 0.55 eV with polarization Ea is observed. The interpretation of this feature is still a puzzle.

We show the optical conductivity σ(ω) of GdVO3 single crystals for the mid-infrared range and temperatures from 10 K to 300 K. In GdVO3, G-type OO (the intermediate phase of YVO3) extends down to the lowest temperatures, offering additional information on the excitations discussed above.
Blake et al., PRB 79, 045101 (2009)
Benckiser et al., NJP 10, 053027 (2008)

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