Pair Correlations, Short Range Order and Dispersive Excitations in the Quasi-Kagome Quantum Magnet Volborthite

Abstract

We present spatial and dynamic information on the s=1/2 distorted kagome antiferromagnet volborthite, Cu3V2O7(OD)2.2D2O, obtained by polarized and inelastic neutron scattering. The instantaneous structure factor, S(Q), is dominated by nearest neighbor pair correlations, with short range order at wave vectors Q1=0.65(3) Å^-1 and Q2=1.15(5) Å^-1 emerging below 5 K. The excitation spectrum, S(Q,ω), reveals two steep branches dispersing from Q1 and Q2, and a flat mode at ω=5.0(2) meV. The results allow us to identify the cross-over at T*=1 K in 51V NMR and specific heat measurements as the build-up of correlations at Q_1. We compare our data to theoretical models proposed for volborthite, and demonstrate that the excitation spectrum can be explained by spin-wave-like excitations with anisotropic exchange parameters, as also suggested by recent local density calculations.

Rewritten article resubmitted to Phys. Rev. Lett. 0211

References in corpus (10)

• Quantum phase transition induced by Dzyaloshinskii-Moriya in the kagome antiferromagnet
• Lattice symmetries and regular states in classical frustrated antiferromagnets
• A Schwinger-boson approach to the kagome with Dzyaloshinskii-Moriya interactions: phase diagram and dynamical structure factors
• Phase Diagram and Spin Dynamics in Volborthite with a Distorted Kagome Lattice
• Valence Bond Glass Phase in the Diluted Kagome Antiferromagnets
• Dzyaloshinskii-Moriya anisotropy and non-magnetic impurities in the $s=1/2$ kagome system ZnCu_3(OH)_6Cl_2
• Spatially Anisotropic Heisenberg Kagome Antiferromagnet
• Quantum and Classical Spins on the Spatially Distorted Kagome Lattice: Applications to Volborthite
• Coupled frustrated quantum spin-1/2 chains with orbital order in volborthite Cu3V2O7(OH)2(H2O)2
• Heisenberg antiferromagnet with anisotropic exchange on the Kagome lattice: Description of the magnetic properties of volborthite

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