Absence of ferromagnetism in VSe2 caused by its charge density wave phase

In this study we present a detailed ab initio analysis of the magnetic properties of VSe2 . Ab initio calculations in the so-called 1T structure yield a ferromagnetic phase as most stable, with a magnetic moment of about 0.6 {\mu} B /V. According to our calculations, and based on the Stoner criterion for itinerant ferromagnets, this ferromagnetic state is on the verge of instability. We have modeled ab initio the charge density wave state reported in the literature. This introduces a periodic lattice distortion leading to a supercell with periodicity 4a x 4a x 3c (4a x 4a for the monolayer) in which we have fully relaxed the atomic positions. We demonstrate that this structural rearrangement causes a strong reduction in the density of states at the Fermi level and the ground state of the system becomes non-magnetic. Experimental evidences that report a magnetic signal need to be understood on the light of this finding.