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arXiv · 1809.10112

Incipient and well-developed entropy plateaus in spin-S Kitaev models

J. Oitmaa·A. Koga·R. R. P. Singh
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Abstract

We present results on entropy and heat-capacity of the spin-S honeycomb-lattice Kitaev models using high-temperature series expansions and thermal pure quantum (TPQ) state methods. We study models with anisotropic couplings $J_z=1\ge J_x=J_y$ for spin values 1/2, 1, 3/2, and 2. We show that for $S>1/2$, any anisotropy leads to well developed plateaus in the entropy function at an entropy value of $\frac{1}{2}\ln{2}$, independent of $S$. However, in the absence of anisotropy, there is an incipient entropy plateau at $S_{max}/2$, where $S_{max}$ is the infinite temperature entropy of the system. We discuss possible underlying microscopic reasons for the origin and implications of these entropy plateaus.

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J. Oitmaa, A. Koga, R. R. P. Singh. 2018-09-26. Incipient and well-developed entropy plateaus in spin-S Kitaev models. https://doi.org/10.1103/physrevb.98.214404

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