Phonon excitations in the quasi-one-dimensional Haldane phase of SrNi2V2O8

Abstract

Vibrational Raman spectra of a single crystal of the coupled Haldane chain compound SrNi 2 V 2 O 8 with uniaxial anisotropy were investigated in the 10-1000 cm −1 frequency range at temperatures 7-300 K. No structural phase transition was observed. The number of phonon lines observed in the experiment and their intensity were analyzed on the basis of the local symmetry considerations of different structural complexes. This approach was successful in explaining the discrepancy between the numbers of expected and experimentally observed phonon lines. Closeness of a real arrangement of some structural units to higher symmetry than the Wyckoff position results in strong interferential quenching of a number of Raman lines in the spectra. PACS: 78.30.-j Infrared and Raman spectra; 63.20.-e Phonons in crystal lattices.

Symmetries of modes in Ni3V2O8: Polarized Raman spectroscopy and ab initio phonon calculations

“…Though there exists report on Raman study on NVO and its solid solutions with substituted Co, Cu, and so forth, the symmetries of Raman active modes are not reported. The symmetries of Raman active modes of a similar compound SrNi 2 V 2 O 8 have been identified by using polarized Raman spectroscopy, but it crystallizes into a tetragonal phase where as NVO is orthorhombic at ambient conditions. The observation of lesser number of modes in SrNi 2 V 2 O 8 than group theoretically predicted number is modelled on the basis of the local symmetry considerations.…”

Non-Abelian statistics in light-scattering processes across interacting Haldane chains

“…Polarized Raman spectra of SrNi 2 V 2 O 8 show all expected phonon modes and their small linewidth and welldefined selection rules indicate the high sample quality. There are no significant phonon anomalies as function of temperatures, and therefore no evidence for a structural instability 23 . At low temperatures (T<30K) and in (ac) scattering geometry we notice two modes, at 22 cm −1 (blue arrow) and at 220 cm −1 (red arrow), see Fig.…”