Raman scattering on the spin-Peierls compound α′-NaV2O5

By means of Raman scattering, we investigated single-crystalline samples of the new inorganic spin-Peierls compound alpha'-NaV2O5 = 34 with T-SP = 34 K. Phonons with anomalous broad line shape indicating a strong spin-phonon coupling above T-SP were detected. Below T-SP several additional modes could be observed. Different temperature dependencies of these modes are interpreted as a first hint that low-energy modes are related to the opening of the spin-Peierls gap observed in neutron scattering experiments while other modes are related to the lowering of the lattice symmetry due to the spin-Peierls transition. (C) 1998 Elsevier Science B.V. All rights reserved.