First principles study of surface effects on electronic and magnetic properties of 2D Cr₂Te₃ material

The effects of surface terminations and thickness are expected to play key roles on the electronic and magnetic properties of two-dimensional (2D) non-van der Waals layered transition metal chalcogenide Cr₂Te₃ materials, which might make them promising candidates for spintronic applications [1]. Our preliminary first principles study using density functional theory (DFT) calculations reveals that bulk Cr₂Te₃ exhibits metallic behavior with ferromagnetic order. We then examined how the different surface terminations (e.g., Te/Te, Cr/Te, Cr/Cr) and thickness (e.g., 1L, 2L, 3L) influence the magnetic ordering and electronic properties of layered Cr_xTe_y. It was found that a magnetic order transforms from a ferromagnetic to a ferrimagnetic order, keeping metallic behavior in the 1L-Te/Te termination. In contrast, other terminations in 1L and Cr/Te termination in 1L-3L still hold bulk-like properties. Interestingly, a transition from the metallic to a half-metallic nature while maintaining bulk-like magnetic properties was found in 1L-3L with Cr/Cr termination. This work provides key insights into the tunability of 2D Cr₂Te₃ and provides a foundation for designing devices at the nanoscale level.