Impact of oxygen adsorption on the electronic properties of titanium nickel surfaces

This study investigates the impact of oxygen adsorption on the electronic properties of the titanium nickel (TiNi) (110) surface using density functional theory (DFT). Surface energy calculations for the (100), (110), and (111) surfaces identify (110) as most stable (0.115 J m⁻² across terminations). On this surface, adsorption at Ti-top, Ni-top, and bridge sites was assessed; the bridge site is most favourable (Eads = −5.111 eV), suggesting strong chemisorption and inducing surface relaxations. Oxygen adsorption introduces localized states near the Fermi level and reduces the DOS at EF. Total and projected DOS highlight Ti 3d, Ni 3d, and O 2p contributions, consistent with partial charge transfer to oxygen and increased surface stability. The work function rises for all sites, with the largest shift for the bridge configuration. These findings elucidate how oxygen alters TiNi surface reactivity and electronic behaviour, providing guidance for improving TiNi performance in oxidizing environments relevant to biomedical, aerospace, and catalytic applications.