Non-collinear ground state from a four-spin chiral exchange in a tetrahedral magnet

I. A. Ado; O. Tchernyshyov; M. Titov

doi:10.1103/physrevlett.127.127204

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arXiv · 2012.07666

Non-collinear ground state from a four-spin chiral exchange in a tetrahedral magnet

I. A. Ado·O. Tchernyshyov·M. Titov

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Abstract

We propose a quartic chiral term $m_x m_y m_z \nabla \cdot \mathbf{m}$ for the energy density of a cubic ferromagnet with broken parity symmetry (point group $T_d$). We demonstrate that this interaction causes a phase transition from a collinear ferromagnetic state to a non-collinear magnetic cone ground state provided its strength exceeds the geometric mean of magnetic exchange and cubic anisotropy. The corresponding non-collinear ground state may also be additionally stabilized by an external magnetic field pointing along certain crystallographic directions. The four-spin chiral exchange does also manifest itself in peculiar magnon spectra and favors spin waves with the wave vector that is perpendicular to the average magnetization direction.

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I. A. Ado, O. Tchernyshyov, M. Titov. 2020-12-14. Non-collinear ground state from a four-spin chiral exchange in a tetrahedral magnet. https://doi.org/10.1103/physrevlett.127.127204

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