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arXiv · 1110.3686

Singlet-triplet excitations and high-field magnetization in CuTe2O5

Zhe Wang·M. Schmidt·Y. Goncharov·Y. Skourski·J. Wosnitza·H. Berger·H. -A. Krug von Nidda·A. Loidl·J. Deisenhofer
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Abstract

By measuring the THz electron spin resonance (ESR) transmission spectra and high-field magnetization on the spin-gapped system CuTe$_2$O$_5$, we identified the singlet-triplet excitations in the dimerized non-magnetic ground state. The determined spin-gap value of $hν_0=4.94$ meV at the $Γ$ point ($\mathbf{Q}\simeq\mathbf{0}$) is significantly smaller than the strongest antiferromagnetic exchange interaction between the Cu ions predicted by theoretical investigations. We also observed the critical field $H_{c1}^{a^*}=37.6$ T for \textbf{H} $\bot$ \emph{bc}-plane and $H_{c1}^{bc}=40.6$ T for \textbf{H} $\|$ \emph{bc}-plane at the onset of non-zero magnetization, consistent with the gap value and corresponding anisotropic \emph{g}-factors determined previously. The observed singlet-triplet excitations in Faraday and Voigt configurations suggest a mixing of the singlet state with the $S_z=0$ triplet state and the $S_z=\pm 1$ triplet states, respectively, due to the Dzyaloshinskii-Moriya (DM) interaction with a DM vector perpendicular to the crystalline \emph{bc}-plane.

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Zhe Wang, M. Schmidt, Y. Goncharov, Y. Skourski, J. Wosnitza, H. Berger, H. -A. Krug von Nidda, A. Loidl, J. Deisenhofer. 2011-11-21. Singlet-triplet excitations and high-field magnetization in CuTe2O5. https://doi.org/10.1143/jpsj.80.124707

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