Ethanol-enabled exfoliation of hematite into few layer hematene with predicted monolayer ferrimagnetism

The exfoliation of non-van der Waals materials into two-dimensional forms remains challenging due to their strong ionic-covalent bonding. Here, we report a combined experimental and theoretical study of hematene exfoliation from hematite, elucidating how solvent-layer interactions control the exfoliation efficiency and structural preservation. Using ultrasound-assisted liquid-phase exfoliation, we show that ethanol and n-butanol yield thinner, more homogeneous few-layer hematene nanosheets than DMF and water under identical conditions, as confirmed by AFM, TEM, SEM, Raman, XRD, and UV-Vis spectroscopy. Density functional theory calculations reveal that, although DMF induces stronger van der Waals interactions and larger interlayer separation, ethanol minimizes structural deformation by enabling controlled lattice relaxation, highlighting the critical role of molecular size and diffusion kinetics in non-van der Waals exfoliation. Beyond the experimentally realized few-layer nanosheets, first-principles calculations predict that an isolated hematene monolayer can stabilize in a compensated ferrimagnetic ground state with negligible net magnetization, out-of-plane magnetic anisotropy, fully spin-polarized transport, and 100% spin-charge conversion near the Fermi level. These results establish ethanol-assisted exfoliation as an effective route toward few-layer hematene and predict that monolayer hematene is a promising platform for future studies of two-dimensional oxide spintronics and ultrafast magnetic switching.