Nonvolatile Electrical Control and Reversible Gas Capture by Ferroelectric Polarization Switching in 2D FeI/InS 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 FeI monolayer and a ferroelectric InS monolayer using density functional theory and the nonequilibrium Green's function method. The results reveal that the FeI monolayer can be reversibly switched between semiconducting and half-metallic properties by nonvolatile control of the InS ferroelectric polarization states. Correspondingly, the proof-of-concept two-probe nanodevice based on the FeI/InS 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 NH, NO, and NO for adsorption on the surface of FeI/InS vdW heterostructures strongly depends on the polarization direction of the ferroelectric layer. In particular, the FeI/InS heterostructure shows reversible capture behavior for NH. As a result, the FeI/InS 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.