Confinement effect enhanced Stoner ferromagnetic instability in monolayer 1T-VSe2

TL;DR

This study uses first-principles calculations to show that the ferromagnetism in monolayer 1T-VSe2 is driven by enhanced Stoner instability due to confinement effects, which can be modulated by interlayer distance.

Contribution

It reveals the intrinsic origin of ferromagnetism in monolayer 1T-VSe2 as driven by enhanced Stoner instability and how it can be modulated by interlayer spacing.

Findings

Ferromagnetism originates from intrinsic Stoner instability.

Confinement effect enhances the density of states at the Fermi level.

Interlayer distance significantly affects the Stoner instability.

Abstract

Monolayer 1T-VSe2 has been reported as a room-temperature ferromagnet. In this work, by using first-principles calculations, we unveil that the ferromagnetism in monolayer 1T-VSe2 is originated from its intrinsic huge Stoner instability enhanced by the confinement effect, which can eliminate the interlayer coupling, and lead to a drastic increase of the density of states at the Fermi level due to the presence of Van Hove singularity. Our calculations also demonstrate that the Stoner instability is very sensitive to the interlayer distance. These results provide a useful route to modulate the nonmagnetic to ferromagnetic transition in few-layers or bulk 1T-VSe2, which also shed light on the enhancement of its Curie temperature by enlarging the interlayer distance.