Layer Dipole Magnetoelectric Polarizability

The layer degree of freedom in two-dimensional (2D) magnetic multilayers acts as a pseudospin with electric-dipole symmetry, enabling electric field control of magnetic behavior—an important goal for spintronics. In this talk, we introduce the notion of the layer dipole magnetoelectric polarizability. This quantity characterizes the magnetization response to a perpendicular electric field through its coupling to the layer dipole moment and can be viewed as the electric analog of the spin magnetoelectric polarizability, which captures the polarization response to an applied Zeeman field. Starting from the orbital magnetization induced by a displacement field, we derive a microscopic expression for this quantity in a minimal bilayer antiferromagnetic model. We evaluate our expression for two concrete systems: a magnetic topological insulator bilayer and a buckled square-lattice model. For the latter, we show that the layer dipole magnetoelectric polarizability contains a quasi-topological contribution, revealing a topological magnetoelectric response in 2D antiferromagnets associated with the layer pseudospin degree of freedom.