Nonvolatile Electrical Control and Reversible Gas Capture by Ferroelectric Polarization Switching in 2D FeI2/In2S3 van der Waals Heterostructures

Nonvolatile electrical control is the core of future magnetoelectric nanodevices. In this work, we systematically explore both the electronic structures and transport properties of multiferroic van der Waals (vdW) heterostructures consisting of a ferromagnetic FeI2 monolayer and a ferroelectric In2S3 monolayer using density functional theory and the nonequilibrium Green's function method. The results reveal that the FeI2 monolayer can be reversibly switched between semiconducting and half-metallic properties by nonvolatile control of the In2S3 ferroelectric polarization states. Correspondingly, the proof-of-concept two-probe nanodevice based on the FeI2/In2S3 vdW heterostructure exhibits a significant valving effect by modulating the ferroelectric switching. Moreover, it is also found that the preference of nitrogen-containing gases such as NH3, NO, and NO2 for adsorption on the surface of FeI2/In2S3 vdW heterostructures strongly depends on the polarization direction of the ferroelectric layer. In particular, the FeI2/In2S3 heterostructure shows reversible capture behavior for NH3. As a result, the FeI2/In2S3 vdW heterostructure-based gas sensor demonstrates high selectivity and sensitivity. These findings may open up a new route for the application of multiferroic heterostructures to spintronics, nonvolatile memories, and gas sensors.