Magnetic interactions and excitations in magnetic 2D van der Waals materials*

Magnetic 2D van der Waals (m2DvdW) materials add new functionality, leading to novel new magnetic 2D devices. Using linear-response ab initio methods, we investigate the magnetic interactions and spin excitations in various m2DvdW systems. Dynamical spin susceptibility is calculated using single-particle Hamiltonians constructed within density-functional theory (DFT) and the quasiparticle self-consistent GW (QSGW) methods. Results are compared with available Inelastic Neutron Scattering (INS) measurements. We found that the more elaborative description of electron interactions better describes the magnetic interactions within 2D van der Waals systems. For example, plain DFT overestimates the exchange couplings in CrI3, while the spin-wave spectrum calculated in QSGW is closer to experiments. The effects of Dzyaloshinskii-Moriya interaction on spin excitations are also discussed.