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arXiv · 2108.05528

Magnetic interactions and spin excitations in van der Waals ferromagnet VI$_3$

Elijah Gordon·V. V. Mkhitaryan·Haijun Zhao·Y. Lee·Liqin Ke
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Abstract

Using a combination of density functional theory (DFT) and spin-wave theory methods, we investigate the magnetic interactions and spin excitations in semiconducting VI$_3$. Exchange parameters of monolayer, bilayer, and bulk forms are evaluated by mapping the magnetic energies of various spin configurations, calculated using DFT+$U$, onto the Heisenberg model. The intralayer couplings remain largely unchanged in three forms of VI$_3$, while the interlayer couplings show stronger dependence on the dimensionality of the materials. We calculate the spin-wave spectra within a linear spin-wave theory and discuss how various exchange parameters affect the magnon bands. The magnon-magnon interaction is further incorporated, and the Curie temperature is estimated using a self-consistently renormalized spin-wave theory. To understand the roles of constituent atoms on magnetocrystalline anisotropy energy (MAE), we resolve MAE into sublattices and find that a strong negative V-I inter-sublattice contribution is responsible for the relatively small easy-axis MAE in VI$_3$.

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Elijah Gordon, V. V. Mkhitaryan, Haijun Zhao, Y. Lee, Liqin Ke. 2021-08-12. Magnetic interactions and spin excitations in van der Waals ferromagnet VI$_3$. https://doi.org/10.1088/1361-6463/ac1bd3

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