EuSn2As2: an exfoliatable magnetic layered Zintl–Klemm phase
Despite the immense interest in magnetic, topological, and magnetoelectronic phenomena in isolated layers of 2D materials and their vertically stacked heterostructures, there remains a dearth of 2D magnetic materials that can be readily exfoliated into single layers. Here, we synthesize EuSn2As2, the first exfoliatable, layered magnetic Zintl–Klemm phase that features van der Waals bonding between neighboring layers. In these crystals, Eu2+ 4f7 spins magnetically order at 24 K and are coupled ferromagnetically within each layer and antiferromagnetically, with some potential canting, across adjacent layers. Magnetic ground state DFT calculations and temperature-dependent transport measurements on single crystals together establish that EuSn2As2 is semimetallic. Finally, we show that this material can be thinned down to a few layers having steps corresponding to SnAsEuAsSn layers via micromechanical exfoliation. This work opens up further explorations into the design, synthesis, and layer-dependent magnetic properties of exfoliatable, lanthanide-based magnetic van der Waals Zintl phases.