Non-collinear spin textures in a lateral heterostructure of nickel-dihalide monolayers

We report structural, electronic, and magnetic properties of a periodic lateral heterostructure of Ni-dihalide monolayers, using ab initio density functional theory (DFT) and Monte Carlo simulations. The heterostructure is constructed by periodically alternating NiBr2 and NiCl2 monolayer ribbons, stitched commensurately along their armchair edges, and exhibiting asymmetric lattice distortions at interfaces due to the differing atomic radii of bromine and chlorine. Electronic band structure calculations reveal an indirect bandgap of 4.15 eV. The magnetic exchange interaction tensor was calculated by DFT-based four-state energy mapping on Heisenberg Hamiltonian, and was subsequently employed in Monte Carlo simulations, revealing distinctly novel spin configurations across the heterostructure, transitioning from spin-spiral and vortex states in the absence of a magnetic field, to skyrmion and anti-skyrmion phases with an external magnetic field applied.