Two-dimensional multiferroic metal with voltage-tunable magnetization and metallicity

Abstract

We design a multiferroic metal that combines seemingly incompatible ferromagnetism, ferroelectricity, and metallicity by hole doping a two-dimensional (2D) ferroelectric with high density of states near the Fermi level. The strong magnetoelectric effect is demonstrated in hole-doped and arsenic-doped monolayer α-In2Se3 using first-principles calculations. Taking advantage of the oppositely charged surfaces created by an out-of-plane polarization, the 2D magnetization and metallicity can be electrically switched on and off in an asymmetrically doped monolayer. The substitutional arsenic defect pair exhibits an intriguing electric field-tunable charge disproportionation process accompanied with an on-off switch of local magnetic moments. The charge ordering process can be controlled by tuning the relative strength of on-site Coulomb repulsion and defect dipole-polarization coupling via strain engineering. Our design principle relying on no transition metal broadens the materials design space for 2D multiferroic metals.

23 pages,5 figures

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Cited by in corpus (3)

• Magnetoelectricity in two-dimensional materials
• Nonlinear phonon Hall effects in ferroelectrics: its existence and non-volatile electrical control
• Doping induced multiferroicity and quantum anomalous Hall effect in $\alpha$-In${}_2$Se${}_3$ thin films