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

Abstract

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 μ B /V. According to our calculations 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 for the bulk. In the monolayer limit the rearrangement induces a Peierls distortion causing an energy gap opening at the Fermi level and the quenching of ferromagnetism.