Journal of magnetism and magnetic materials vol:272 issue:Suppl. 1 pages:E657-E658
date:Katholieke Univ Leuven, Lab Vaste Stoffys & Magnetisme, B-3001 Louvain, Belgium; Leiden Univ, Inst Lorentz Theoret Phys, NL-2300 RA Leiden, Netherlands; Univ Valencia, Inst Mat Sci, Valencia 46071, Spain; Univ Tokyo, Inst Solid State Phys, Chiba 2778581, Japan
The phonon dynamics in NaTiSi2O6 is studied using the Raman scattering technique. The observed phonon anomalies around T = 210 K combined with theoretical considerations show that the high-temperature dynamical Jahn - Teller phase of NaTiSi2O6 exhibits a spontaneous breaking of translational symmetry into an orbital dimerized state. We describe this phase instability as an orbital analogue of the spin-Peierls phase transition. (C) 2004 Elsevier B.V. All rights reserved.