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arXiv · 1304.3361

Electronic structure of KTi(SO4)2.H2O - a S=1/2 frustrated chain antiferromagnet

Deepa Kasinathan·K. Koepernik·O. Janson·G. J. Nilsen·J. O. Piatek·H. M. Ronnow·H. Rosner
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Abstract

The compound KTi(SO4)2.H2O was recently reported as a quasi one-dimensional spin 1/2 compound with competing antiferromagnetic nearest neighbor exchange J1 and next-nearest neighbor exchange J2 along the chain with a frustration ratio alpha = J2/J1 ~ 0.29 [Chem. Mater. vol. 20, pg. 8 (2008)]. Here, we report a microscopically based magnetic model for this compound derived from density functional electronic structure calculations along with respective tight-binding models. Our calculations confirm the quasi one-dimensional nature of the system with antiferromagnetic J1 and J2, but suggest a significantly larger frustration ratio alpha ~ 1.1 +- 0.2. Based on transfer matrix renormalization group calculations we found that, due to an intrinsic symmetry of the J1-J2 model, our larger frustration ratio alpha is also consistent with the previous thermodynamic data. To resolve this issue, we propose performing high-field magnetization measurements and low temperature susceptibility measurements which should allow to precisely identify the frustration ratio alpha.

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Deepa Kasinathan, K. Koepernik, O. Janson, G. J. Nilsen, J. O. Piatek, H. M. Ronnow, H. Rosner. 2013-04-11. Electronic structure of KTi(SO4)2.H2O - a S=1/2 frustrated chain antiferromagnet. https://doi.org/10.1103/physrevb.88.224410

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