Ground-state and thermodynamic properties of the spin-1/2 Heisenberg model on the anisotropic triangular lattice
Etat fondamental et propriétés thermodynamiques su modèle Heisenberg de spin 1/2 sur le réseau triangulaire anisotrope
Résumé
The spin- 1/2 triangular lattice antiferromagnetic Heisenberg model has been for a long time the prototypical model of magnetic frustration. However, only very recently this model has been proposed to be realized in the Ba _8CoNb_6O _{24} compound. The ground-state and thermodynamic properties are evaluated from a high-temperature series expansion interpolation method, called ``entropy method’’, and compared to experiments. We find a ground-state energy e0 = -0.5445(2) e0 = − 0.5445 ( 2 ) in perfect agreement with exact diagonalization results. We also calculate the specific heat and entropy at all temperatures, finding a good agreement with the latest experiments, and evaluate which further interactions could improve the comparison. We explore the spatially anisotropic triangular lattice and provide evidence that supports the existence of a gapped spin liquid between the square and triangular lattices.
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