First-principles calculations of interface engineering for 2D α-In2Se3-based van der Waals multiferroic heterojunctions

Abstract

The external electrical/light induced Schottky-to-Ohmic contact transition in van der Waals (vdW) multiferroic heterojunctions is a key technological breakthrough in the low-resistance nanodevices. However, this transition usually faces the challenge of strong Fermi level pinning effect at heterointerface. Herein, we employ density functional theory to explore the interface contact properties in α-In2Se3/1T-MX2 (M = Mn, V, Cr; X = Se, Te) vdW heterojunctions, where α-In2Se3 has two opposite polarization states (α-P↑ and α-P↓). We find that only the case of 1T-MnSe2 maintains the initial crystal structure with being affected by electrical polarization of α-In2Se3. Moreover, α-In2Se3/1T-MnSe2 shows an enhanced p-type Schottky barrier in α-In2Se3 with α-P↑ state, while it can exhibit n-type Ohmic contact when α-In2Se3 reverses to α-P↓ state. Further kinetic analysis reveals that this transition is non-volatile and intrinsic. Our results provide an avenue for the design of future 2D non-volatile electronics.