VI3 - a new layered ferromagnetic semiconductor

TL;DR

This paper reports the discovery of ferromagnetism in the layered 2D semiconductor VI3, which exhibits ferromagnetic ordering at 49 K, has a 0.6 eV band gap, and can have its magnetic domains manipulated externally.

Contribution

It introduces VI3 as a new layered ferromagnetic semiconductor with unique structural and magnetic properties at the 2D limit.

Findings

VI3 becomes ferromagnetic at 49 K

Exhibits a 0.6 eV optical band gap

Magnetic domains are manipulable by external fields

Abstract

Two-dimensional (2D) materials are promising candidates for next-generation electronic devices. In this regime, insulating 2D ferromagnets, which remain rare, are of special importance due to their potential for enabling new device architectures. Here we report the discovery of ferromagnetism in a layered van der Waals semiconductor, VI3, which is based on honeycomb vanadium layers separated by an iodine-iodine van der Waals gap. It has a BiI3-type structure (R-3, No.148) at room temperature, and our experimental evidence suggests that it may undergo a subtle structural phase transition at 78 K. VI3 becomes ferromagnetic at 49 K, below which magneto-optical Kerr effect imaging clearly shows ferromagnetic domains, which can be manipulated by the applied external magnetic field. The optical band gap determined by reflectance measurements is 0.6 eV, and the material is highly resistive.