Exchange interactions and spin dynamics in the layered honeycomb ferromagnet CrI${}_3$

Abstract

We derive the microscopic spin Hamiltonian for rhombohedral CrI${}_3$ using extensive first-principles density functional theory (DFT) calculations which incorporate spin-orbit coupling and Hubbard U. Our calculations indicate a dominant nearest-neighbor ferromagnetic Heisenberg exchange with weaker further-neighbor Heisenberg terms. In addition, we find a Dzyaloshinskii-Moriya interaction which primarily drives a topological gap in the spin-wave spectrum at the Dirac point, and uncover a non-negligible antiferromagnetic Kitaev coupling between the S=3/2 Cr moments. The out-of-plane magnetic moment is stabilized by weak symmetric bond-dependent terms and a local single-ion anisotropy. Using linear spin wave theory, we find that our exchange parameters are in reasonably good agreement with inelastic neutron scattering (INS) experiments. Employing classical Monte Carlo simulations, we study the magnetic phase transition temperature $T_c$ and its evolution with an applied in-plane magnetic field. We further demonstrate how future high-resolution INS experiments on the magnon dispersion of single crystals in an in-plane magnetic field may be used to quantitatively extract the strength of the antiferromagnetic Kitaev exchange coupling.

10 pages, 10 figures

References in corpus (8)

• Graphene Spintronics
• Ising-Type Magnetic Ordering in Atomically Thin FePS3
• Atomic-scale control of graphene magnetism using hydrogen atoms
• Proximity-induced ferromagnetism in graphene revealed by anomalous Hall effect
• Magnetic Moment Formation in Graphene Detected by Scattering of Pure Spin Currents
• Feedback-optimized parallel tempering Monte Carlo
• Magnetic field effect on topological spin excitations in CrI${}_3$
• Uniaxial pressure effects in the two-dimensional van-der-Waals ferromagnet CrI${}_3$

Cited by in corpus (4)

• Beyond Kitaev physics in strong spin-orbit coupled magnets
• Microscopic origin of magnetism in monolayer $3d$ transition metal dihalides
• Ligand-SOC enhanced $4f^5$ Kitaev antiferromagnet: Application to ${\mathrm{SmI}}_3$
• Spin-orbit coupling controlled two-dimensional magnetism in chromium trihalides