Ferroelectric heterointerface control of spin polarization in a Janus antiferromagnet and its application in multistate storage†

Abstract

With the successful fabrication of two-dimensional (2D) magnets and ferroelectrics, constructing multiferroic van der Waals (vdW) heterostructures offers a practicable route toward high-performance nanoelectronics and spintronics device technology. In this work, based on first-principles calculations, we propose a Mn₂ClF/Sc₂CO₂ vdW multiferroic heterostructure by stacking the A-type antiferromagnetic (AFM) material Mn₂ClF and the 2D ferroelectric material Sc₂CO₂. Our findings demonstrate that the AFM layer Mn₂ClF will transition between semiconductor and half-metal by reversing the ferroelectric polarization state of the Sc₂CO₂ layer. This transition is attributable to the different band alignments of Mn₂ClF and Sc₂CO₂ for different polarization states. Then, we design a multiferroic tunnel junction (MFTJ) based on the Sc₂CO₂/Mn₂ClF/Sc₂CO₂ vdW multiferroic heterostructure, which realizes the function of four-state information storage. Furthermore, we show that the spin polarization of near 100% is achieved by applying a small bias on the MFTJ. These results present a promising avenue for the application of multifunctional spintronic devices.