Title: Super-lattice and Magnetic Order in Iron Intercalated Bilayer Tantalum Disulfide

Atomically thin, magnetically doped transition metal dichalcogenides (TMDCs) are promising 2D magnets, offering significant tunability over existing 2D magnets that derive their magnetism from the host lattice. However as synthetic routes have only been recently developed for thin film intercalated magnets, the phase space in these materials has not yet been studied computationally. We investigate iron intercalated bilayer 2H-TaS2 with density functional theory, results from which predict a relatively large magnetic anisotropy favoring c-axis orientation, magnetic behavior strongly coupled to the local crystal field symmetry and thus the van der waals gap, and a strong preference for octahedral site occupancy. The Ising-type spins, strong preference for octahedral site occupation, and low magnetic ordering temperature permit use of a simple decoupled treatment of magnetic and super-lattice order. The resultant lattice Hamiltonian is investigated with Monte Carlo to predict the magnetic and intercalant phase space of this material and how it can be manipulated via strain and doping.