Insulating antiferromagnetism in VTe

We report a comprehensive theoretical and experimental study on the vanadium monotelluride VTe, which crystallizes in the NiAs hexagonal structure. First principles calculations reveal a complex hierarchy of magnetic interactions and energy scales, with the ground state theoretically determined as an (1/2,0,1) antiferromagnetic ordering with insulating character and a band gap of 0.5 eV. These interactions vary significantly from a nearest-neighbor or extended Heisenberg-like model, suggesting a similarity to the parent state of the iron-based superconductors and the possibility of superconductivity if appropriately doped. Experimental synthesis and characterization efforts find a substantially off-stoichiometric orthorhombic structure (a defect NiAs structure) with composition V$_{0.85}$Te, and an apparent Neel point of some 45 K. Our first principles calculations find the stoichiometric phase VTe to have a negative Vanadium defect formation energy, thus explaining the formation of the off-stoichiometric phase.