Diversified Magnetoelectric Coupling in 2D Multiferroic Materials

Multiferroic materials with coupled magnetism and ferroelectricity, even though scarcely exist in nature, are highly desirable for efficient “electric writing + magnetic reading”. Currently, the polarization and magnetization of traditional multiferroics with strong magnetoelectric coupling are all too weak for practical applications. Here we show first-principles evidences that strong magnetoelectrics can be realized in a series of 2D multiferroics: in some intercalated bilayer systems, their “mobile” magnetism can be controlled by ferroelectric switching upon external electric field, exhibiting either “on” state with spin-selective and highly p-doped channels, or “off” state insulating for both spin and electron transport, which renders efficient electrical writing and magnetic reading; vertical polarization can be maintained against depolarizing field, rendering high-density data storage possible. In some 2D systems, the magnetization can be switched by 90 or even 180 degree upon ferroelectric switching.
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