CrS2 monolayer: Synthesis, electronic structure, and magnetic properties

Two-dimensional transition-metal dichalcogenides provide an ideal platform for exploring emergent electronic and magnetic phenomena inaccessible in bulk materials. Here, we realize a metastable monolayer CrS2 film on bilayer graphene/SiC(0001) by combining molecular-beam epitaxy with a topotactic chemical reaction. Angle-resolved photoemission spectroscopy (ARPES), together with first-principles calculations, supports the assignment of monolayer CrS2 to the octahedral 1T structure. ARPES reveals a gap-like semiconducting state that is not reproduced by the GGA+U calculations. X-ray magnetic circular dichroism detects no ferromagnetic response in monolayer 1T-CrS2 down to 160 K, consistent with paramagnetic or antiferromagnetic behavior, in stark contrast to its isostructural counterpart, monolayer CrTe2, which exhibits metallic ferromagnetic behavior. These results establish metastably stabilized monolayer CrS2 as a distinct member of Cr-based two-dimensional materials and provide a foundation for exploring ultrathin semiconductor devices.