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arXiv · 0801.2533

Correlation between spin helicity and electric polarization vector in quantum-spin chain magnet LiCu$_2$O$_2$

S. Seki·Y. Yamasaki·M. Soda·M. Matsuura·K. Hirota·Y. Tokura
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Abstract

Measurements of polarized neutron scattering were performed on a $S=1/2$ chain multiferroic LiCu$_2$O$_2$. In the ferroelectric ground state with the spontaneous polarization along the c-axis, the existence of transverse spiral spin component in the $bc$-plane was confirmed. When the direction of electric polarization is reversed, the vector spin chirality as defined by ${\bf C}_{ij} = {\bf S}_i \times {\bf S}_j$ ($i$ and $j$ being the neighboring spin sites) is observed to be reversed, indicating that the spin-current model or the inverse Dzyaloshinskii-Moriya mechanism is applicable even to this $e_{\mathrm{g}}$-electron quantum-spin system. Differential scattering intensity of polarized neutrons shows a large discrepancy from that expected for the classical-spin $bc$-cycloidal structure, implying the effect of large quantum fluctuation.

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S. Seki, Y. Yamasaki, M. Soda, M. Matsuura, K. Hirota, Y. Tokura. 2008-01-16. Correlation between spin helicity and electric polarization vector in quantum-spin chain magnet LiCu$_2$O$_2$. https://doi.org/10.1103/physrevlett.100.127201

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