  We have carried out density-functional theory (DFT) calculations to study the
magnetic stability of both ferromagnetic (FM) and anti-ferromagnetic (AFM)
states in monolayer 1T-CrTe2. Our results show that the AFM order is lower in
energy and thus is the ground state. By tuning the lattice parameters, the AFM
order can transition to the FM order, in good agreement with experimental
observation. We observe a commensurate SDW alongside the previously predicted
CDW, and attribute the AFM order to the SDW. This results in distinct hole and
electron Fermi pockets and a pronounced optical anisotropy, suggesting
quasi-one-dimensional behavior in this material.
