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Magnetic Excitations of the Spin Gap System TlCuCl$_3$

A. Oosawa·T. Kato·H. Tanaka·K. Kakurai·M. Mueller·H. -J. Mikeska
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Abstract

TlCuCl$_3$ has a singlet ground state with the excitation gap $Δ=0.65$ meV. The magnetic excitations in TlCuCl$_3$ have been investigated by means of neutron inelastic scattering experiments. The constant-$\it{\pmb Q}$ energy scan profiles were collected in the $a^*-c^*$ plane. A well-defined single magnetic excitation mode was observed. The dispersion relations along four different directions were determined. The lowest excitation occurs at ${\it{\pmb Q}}=(h, 0, l)$ with integer $h$ and odd $l$, as observed in KCuCl$_3$. A cluster series expansion up to the sixth order was applied to analyze the dispersion relations, and the individual exchange interactions were evaluated. It was demonstrated that TlCuCl$_3$ is a strongly coupled spin-dimer system.

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A. Oosawa, T. Kato, H. Tanaka, K. Kakurai, M. Mueller, H. -J. Mikeska. 2002-01-28. Magnetic Excitations of the Spin Gap System TlCuCl$_3$. https://arxiv.org/abs/cond-mat/0108130

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