Intrinsic 2D Ferromagnetism in V5Se8 Epitaxial Thin Films

TL;DR

This paper reports the discovery of intrinsic 2D ferromagnetism in V5Se8 thin films grown via MBE, showing emergent ferromagnetic properties in a material that is antiferromagnetic in bulk, with potential for spintronics.

Contribution

It demonstrates that V5Se8 epitaxial thin films exhibit emergent 2D ferromagnetism despite their bulk antiferromagnetic nature, expanding the class of 2D magnetic materials.

Findings

V5Se8 thin films show intrinsic 2D ferromagnetism.

The ferromagnetism is emergent despite bulk antiferromagnetic properties.

The material behaves as an itinerant 2D Heisenberg ferromagnet.

Abstract

The discoveries of intrinsic ferromagnetism in atomically-thin van der Waals crystals have opened up a new research field enabling fundamental studies on magnetism at two-dimensional (2D) limit as well as development of magnetic van der Waals heterostructures. To date, a variety of 2D ferromagnetism has been explored mainly by mechanically exfoliating 'originally ferromagnetic (FM)' van der Waals crystals, while bottom-up approach by thin film growth technique has demonstrated emergent 2D ferromagnetism in a variety of 'originally non-FM' van der Waals materials. Here we demonstrate that V5Se8 epitaxial thin films grown by molecular-beam epitaxy (MBE) exhibit emergent 2D ferromagnetism with intrinsic spin polarization of the V 3d electrons despite that the bulk counterpart is 'originally antiferromagnetic (AFM)'. Moreover, thickness-dependence measurements reveal that this newly-developed 2D ferromagnet could be classified as an itinerant 2D Heisenberg ferromagnet with weak magnetic anisotropy, broadening a lineup of 2D magnets to those potentially beneficial for future spintronics applications.