Antiferromagnetic order and magnetoelectricity of 2D charge carriers

Ordinary materials react to an electric field by generating an electrical polarization, and a magnetic field normally generates a magnetization. In magnetoelectric media, this conventional scheme is turned upside-down: an electric polarization is induced by a magnetic field and a magnetization results from an electric field. We develop a detailed theory for how this effect comes about in materials nanostructured into ultra-thin conducting sheets. Such quantum wells are found to exhibit a sizable magnetoelectric effect that could enable novel device applications. Antiferromagnetic order plays a central role in our theory. We reveal magnetic order in quantum-well structures to arise from dissipationless equilibrium currents. In the magnetoelectric effect, an electric field manipulates the antiferromagnetic currents such that they give rise to a macroscopic net magnetization. Our theory provides new avenues for pursuing antiferromagnetic spintronics as a post-silico electronics paradigm.