Magnetic properties of bilayer VI3: Role of trigonal crystal field and electric-field tuning

TL;DR

This study investigates the magnetic properties of bilayer VI3, emphasizing the influence of trigonal crystal fields and electric fields, revealing potential for electric control of magnetic states in spintronic applications.

Contribution

It provides a first-principles analysis of trigonal crystal-field effects in VI3 bilayers and demonstrates electric-field tuning of magnetic states, advancing understanding of 2D magnetic materials.

Findings

Trigonal crystal field stabilizes insulating state in VI3 bilayers.

Interlayer magnetic interactions are influenced by specific hopping channels.

Electric field can switch magnetic ground state from antiferromagnetic to ferromagnetic.

Abstract

The magnetic properties of two-dimensional VI3 bilayer are the focus of our first-principles analysis, highlighting the role of trigonal crystal-field effects and carried out in comparison with the CrI3 prototypical case, where the effects are absent. In VI3 bilayers, the empty a1g state - consistent with the observed trigonal distortion - is found to play a crucial role in both stabilizing the insulating state and in determining the inter-layer magnetic interaction. Indeed, an analysis based on maximally localized Wannier functions allows to evaluate the interlayer exchange interactions in two different VI3 stackings (labelled AB and AB'), to interpret the results in terms of virtual-hopping mechanism, and to highlight the strongest hopping channels underlying the magnetic interlayer coupling. Upon application of electric fields perpendicular to the slab, we find that the magnetic ground-state in the AB' stacking can be switched from antiferromagnetic to ferromagnetic, suggesting VI3 bilayer as an appealing candidate for electric-field-driven miniaturized spintronic devices.