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arXiv · 1912.11240

Thermodynamic properties of an $S=1/2$ ring-exchange model on the triangular lattice

Kazuhiro Seki·Seiji Yunoki
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Abstract

By using a numerically exact diagonalization technique and a block-extended version of the finite-temperature Lanczos method, we study thermodynamic properties of an $S=1/2$ Heisenberg model on the triangular lattice with an antiferromagnetic nearest-neighbor interaction $J$ and a four-spin ring-exchange interaction $J_{\rm c}$. Calculations are performed on small clusters under the periodic-boundary conditions. In contrast to the purely triangular case with $J_{\rm c}=0$, the specific heat exhibits a characteristic double-peak structure for $J_{\rm c}/J \gtrsim 0.04$. From the calculation of the entropy and the uniform magnetic susceptibility, it is shown that non-magnetic excitations exist below the magnetic excitation for $J_{\rm c}/J \gtrsim 0.04$.

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Kazuhiro Seki, Seiji Yunoki. 2020-06-04. Thermodynamic properties of an $S=1/2$ ring-exchange model on the triangular lattice. https://doi.org/10.1103/physrevb.101.235115

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