Jahn–Teller Effects and Spintronic Behaviors in a Ti-Doped ScSI Monolayer

The geometric and electronic properties of the recently emerged two-dimensional material ScSI substitutionally doped by Ti atoms in one atomic layer are studied employing density functional theory. The Jahn–Teller effect is greatly enhanced around a Ti dopant due to the distorted octahedral geometry of its coordinate atoms. Besides the much enlarged energetic separation between e g and t 2g orbital groups, the d y ̅ z orbital separates from the d x ̅ z and d x ̅ y ̅ orbitals in the t 2g orbital group. The material becomes a half-semiconductor when one Sc atom is replaced by a Ti atom in each 2 × 2 supercell, and only the spin-up d y ̅ z orbital is occupied. The material remains a half-semiconductor if the Ti dopants align in a specific direction at higher doping concentrations and may convert into a half-metal otherwise. It becomes a strongly magnetized metal when the Sc atoms in a whole atomic layer are replaced by Ti atoms. Ti-doped ScSI is expected to be promising in the application of spintronics.