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Spin-Peierls transition in TiOCl

M. Shaz·S. van Smaalen·L. Palatinus·M. Hoinkis·M. Klemm·S. Horn·R. Claessen
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Abstract

Temperature-dependent x-ray diffraction of the low-dimensional spin 1/2 quantum magnet TiOCl shows that the phase transition at T_{c2} = 90 K corresponds to a lowering of the lattice symmetry. Below T_{c1} = 66 K a twofold superstructure develops, that indicates the formation of spin-singlet pairs via direct exchange between neighboring Ti atoms, while the role of superexchange is found to be negligible. TiOCl thus is identified as a spin-Peierls system of pure 1D chains of atoms. The first-order character of the transition at T_{c1} is explained by the competition between the structurally deformed state below T_{c2} and the spin-Peierls state below T_{c1}.

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M. Shaz, S. van Smaalen, L. Palatinus, M. Hoinkis, M. Klemm, S. Horn, R. Claessen. 2005-03-09. Spin-Peierls transition in TiOCl. https://doi.org/10.1103/physrevb.71.100405

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