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arXiv · 1305.4042

Ghost modes and continuum scattering in the dimerized distorted kagome lattice antiferromagnet Rb$_2$Cu$_3$SnF$_{12}$

K. Matan·Y. Nambu·Y. Zhao·T. J. Sato·Y. Fukumoto·T. Ono·H. Tanaka·C. Broholm·A. Podlesnyak·G. Ehlers
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Abstract

High intensity pulsed neutron scattering reveals a new set of magnetic excitations in the pinwheel valence bond solid state of the distorted kagome lattice antiferromagnet Rb$_2$Cu$_3$SnF$_{12}$. The polarization of the dominant dispersive modes (2 meV $<\hbarω< $7 meV) is determined and found consistent with a dimer series expansion with strong Dzyaloshinskii-Moriya interactions ($D/J=0.18$). A weakly dispersive mode near 5 meV and shifted "ghosts" of the main modes are attributed to the enlarged unit cell below a $T=215$ K structural transition. Continuum scattering between 8 meV and 10 meV might be interpreted as a remnant of the kagome spinon continuum [T.-H. Han et al., Nature 492, 406 (2012)]

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K. Matan, Y. Nambu, Y. Zhao, T. J. Sato, Y. Fukumoto, T. Ono, H. Tanaka, C. Broholm, A. Podlesnyak, G. Ehlers. 2013-12-28. Ghost modes and continuum scattering in the dimerized distorted kagome lattice antiferromagnet Rb$_2$Cu$_3$SnF$_{12}$. https://doi.org/10.1103/physrevb.89.024414

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