Fabrication of large-area 2D magnetic semiconductor films for low-temperature ARPES

The exploration of two-dimensional (2D) magnetic semiconductors is often hindered by small lateral sample sizes and rapid degradation under ambient conditions. In angle-resolved photoemission spectroscopy (ARPES), sample charging at low temperatures further complicates the investigation of magnetic phases with low transition temperatures. Here, we introduce a cost-effective, simple, and readily implementable preparation technique to address these challenges and enable the study of thin 2D magnetic semiconductor films in surface science experiments at very low temperatures. Our method involves thermally depositing a thin gold film onto a cleaved van der Waals (vdW) crystal. While this process damages the vdW layers in direct contact with the gold, preventing the isolation of few-layer samples, it ensures strong and uniform bonding across the crystal surface. Exfoliation under ultra-high vacuum conditions yields vdW films that are hundreds of nanometers thick and extend over hundreds of micrometers, as confirmed by atomic force microscopy. ARPES measurements on an exfoliated FePS₃ film at 6 K reveal its band structure in the antiferromagnetic phase, demonstrating both surface cleanliness and, crucially, the suppression of sample charging enabled by our preparation method.