Noncollinear ferrielectricity and hydrogen-induced ferromagnetic polar half-metallicity in MnO3Cl

Collinear dipole orders such as ferroelectricity and antiferroelectricity have developed rapidly in last decades. While, the noncollinear dipole orders are rarely touched in solids. Noncollinear dipole orders can provide a route to realize ferrielectricity. Based on first-principles calculations, an inorganic molecular crystal MnO3Cl has been demonstrated to own intrinsic noncollinear ferrielectricity, which originates from the stereo orientations of polar molecules. The large negative piezoelectricity effect (d33 ∼ -27 pC/N) is also predicted. A strong light absorption and moderate optical anisotropy are found for this molecular crystal in the ultraviolet light window. Additionally, by electron doping via hydrogen intercalation, a ferromagnetic polar half-metals can be obtained. Our study here provide a material platform to explore the intriguing physics of noncollinear ferrielectricity and potential applications in devices.