Magnetic properties of atomic 3d transition-metal chains on S-vacancy-line templates of monolayer MoS2: effects of substrate and strain

The unique tri-layered atomic structure of MoS2 monolayer favors formation of sulfur vacancy lines (SVL), which has been confirmed by both theoretical and experimental studies. This defect could be used as a template to accommodate atomic metal chains, which is an interesting research topic in recent years. In this study, we investigated the magnetic properties of atomic 3d transition metal (V, Cr, Mn and Fe) chains adsorbed along a SVL of monolayer MoS2 using first-principles calculations. All atomic transition-metal (TM) chains could adsorb stably with large binding energies. The magnetic orders and exchange interactions of 3d transition-metal chains were dramatically influenced by the MoS2 substrate. The magnetic ground state of the V and Cr chains remained unchanged after anchoring onto MoS2; however the magnetic interactions weakened compared to those of their free-standing cases. Mn and Fe chains showed transitions from ferromagnetic (FM) coupling in a freestanding chain to antiferromagnetic (AFM) coupling on the SVL of MoS2. The magnetic coupling in atomic transition metal chains is mediated by Mo atoms in the vicinity of atomic chains, which is governed by the combination of through-bond and through-space interactions. It was found that through-bond coupling is dominant in FM V/MoS2, and through-space coupling is dominant in the AFM state of Cr/MoS2, Mn/MoS2 and Fe/MoS2. The electronic properties, magnetic order and exchange interactions of atomic 3d transition-metal chain on SVL of MoS2 can be tuned by the uniaxial strain applied along the chain direction.