Engineering Collinear Magnetization in Hexagonal LuFeO3 and Magnetoelectric Control of Skyrmions in Hexagonal 2D Epilayers

Abstract Cubic, perovskite‐structure ABO 3 ‐ and A 1− x A' x BO 3 ‐type oxides have been investigated extensively while their hexagonal structure versions have not, even though they are multiferroic and can form heterostructures with hexagonal 2D materials. In particular, multiferroic 2D epilayers may lead to strong magnetoelectric coupling. Hexagonal RFeO 3 ferrites, where R is a rare‐earth element (Lu, Yb, etc.), are excellent candidates, but their ferromagnetism is weak. In this work, density‐functional‐theory (DFT) calculations are employed and first show that heavy electron doping of hexagonal LuFeO 3 ( h ‐LFO), namely Lu 1− x Hf x FeO 3 ( h ‐LHFO), leads to spin‐disproportionation of the Fe sublattices and, especially for x = 1/2 and 2/3, to robust, room‐temperature, out‐of‐plane, collinear ferrimagnetism that is stabilized by a Jahn–Teller metal‐to‐insulator transition. h ‐LHFO/ h ‐2D heterostructures are then shown, where h ‐2D is the FE/FM monolayer MnSTe, to stabilize skyrmions without an external magnetic field and their chirality is controlled by an external electric field through the h ‐LHFO polarization, opening up a new realm for magnetoelectric applications.