Electric Dzyaloshinskii-Moriya Interaction: its existence and electronic origin

The magnetic Dzyaloshinskii-Moriya Interaction (mDMI) revolutionized magnetism, since it is, e.g., at the heart of nontrivial non-collinear topological textures, such as vortices, skyrmions, and domain walls – that are fundamentally intriguing and technologically promising. Recently, experiments and numerical simulations have revealed the existence of topologically nontrivial electrical polar textures, that are the electrical counterparts of magnetic topological defects. Strikingly, their origins were typically assumed to be related to electrostatic boundary conditions rather than an intrinsic hypothetical electric analogous of the mDMI, that is an electric Dzyaloshinskii-Moriya Interaction (eDMI). In fact, such eDMI has long been assumed not to exist. In this poster, I will demonstrate the existence of eDMI. Moreover, I will show that (i) both eDMI and mDMI need electron hopping channels and local-inversion-symmetry breaking to occur; (ii) mDMI needs spin-orbit coupling (soc) to connect spin up and down, unlike eDMI; (iii) eDMI naturally exists in polar materials because of the general existence of local-inversion-symmetry breaking. Our results, therefore, suggest the existence of a new paradigm of noncollinear polar arrangements arising from intrinsic electric Dzyaloshinskii-Moriya Interaction.