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arXiv · 1812.10155

Thermodynamics and spin mapping of quantum excitations in a Heisenberg spin heptamer

A. Roxburgh·J. T. Haraldsen
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Abstract

In this study, we examine the thermodynamics and spin dynamics of spin-1/2 and spin-3/2 heptamers. Through an exact diagonalization of the isotropic Heisenberg Hamiltonian, we find the closed-form, analytical representations for thermodynamic properties, spin excitations, and neutron scattering structure factors. Furthermore, we investigate the {cluster-like excitations of quantum spin heptamer} in the three-dimensional pyrochlore lattice material MgCr$_2$O$_4$. Using a spin mapping of the spin-1/2 heptamer excitations, the calculated structure factors of the spin-3/2 heptamer are be determined, which provides clarification for the spin excitations in MgCr$_2$O$_4$. Overall, this study demonstrates the ability to use the spin mapping of structure factors for small spin systems to analyze more complex structures.

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A. Roxburgh, J. T. Haraldsen. 2018-12-25. Thermodynamics and spin mapping of quantum excitations in a Heisenberg spin heptamer. https://doi.org/10.1103/physrevb.98.214434

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