Spin gap behavior and charge ordering in α^{\prime}-NaV_2O_5 probed by light scattering

Abstract

We present a detailed analysis of light scattering experiments performed on the quarter-filled spin ladder compound ${\alpha }^{\prime }$-NaV${}_2$O${}_5$ for the temperature range 5 K$\le$T$\le$300 K. This system undergoes a phase transition into a singlet ground state at T=34 K accompanied by the formation of a super structure. For T$\le$34 K several new modes were detected. Three of these modes are identified as magnetic bound states. Experimental evidence for charge ordering on the V sites is detected as an anomalous shift and splitting of a V-O vibration at 422 cm${}^{-1}$ for temperatures above 34 K. The smooth and crossover-like onset of this ordering at T${}_{\mathrm{CO}}$= 80 K is accompanied by pretransitional fluctuations both in magnetic and phononic Raman scattering. It resembles the effect of stripe order on the super structure intensities in La${}_2$NiO${}_{4+\delta }$.

36 pages, 11 figures, accepted for publication in PRB (sept.99)

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Cited by in corpus (20)

• Magnetic light scattering in low-dimensional quantum spin systems
• Electron-phonon and spin-phonon coupling in NaV${}_2$O${}_5$: charge fluctuations effect
• Charge Order in NaV2O5 studied by EPR
• Raman scattering study of anomalous charge-, spin-, and lattice-dynamics in the charge-ordered phase of ${\mathbf{Bi}}_{1-x}{\mathbf{Ca}}_x{\mathbf{MnO}}_3$ ($x>0.5$)
• Lattice vibrations of alpha'-NaV_2O_5 in the low-temperature phase. Magnetic bound states?
• Infrared and Raman spectra of LiV2O5 single crystals
• Pressure-induced changes in the optical properties of quasi-one-dimensional $\beta$-Na${}_{0.33}$V${}_2$O${}_5$
• Optical properties, electron-phonon coupling, and Raman scattering of vanadium ladder compounds
• Unconventional anisotropic superexchange in NaV2O5
• Spin-Peierls transition in NaV2O5 in high magnetic fields
• Charge ordering in quarter-filled ladder systems coupled to the lattice
• Single-particle spectral function of quarter-filled ladder systems
• Discussion of a spin-cluster model for the low temperature phase of NaV_2O_5
• Charge density waves in Sr_14-xCa_xCu_24O_41: electron correlations vs. structural effects
• Charge kinks as Raman scatterers in quarter-filled ladders
• Dzyaloshinskii-Moriya interaction in NaV${}_2$O${}_5$: a microscopic study
• Charge order induced by electron-lattice interaction in NaV2O5
• Scaling of excitations in dimerized and frustrated spin-1/2 chains
• Electronic Properties of α'-NaV_2O_5
• Charge-ordering phase transition and order-disorder effects in the Raman spectra of NaV2O5