Surface segregation of Pt in L10-MnGa(001): Reconstruction-induced stabilization and reactivity insights from first-principles

This work provides a first-principles analysis of Platinum (Pt) atom behavior on the L 10 -MnGa(001) surface, focusing on its segregation, structural stability, and chemical reactivity. The research demonstrates that Pt atoms energetically favor the occupying sites on the surface and subsurface layers of L 10 -MnGa. This tendency for surface segregation leads to the formation of a stable 1 × 2 surface reconstruction, where a Pt atom substitutes a first-layer Manganese (Mn) atom. This finding is consistent across different simulated growth conditions and aligns with previous experimental observations. Furthermore, the study explores the chemical reactivity of these Pt-modified surfaces. Electrostatic potential analysis reveals that exposed Pt atoms on the surface act as active sites for molecular adsorption. The system shows significant potential for hydrogen activation, as evidenced by the partial weakening of the H H bond when a hydrogen molecule (H 2 ) is adsorbed onto a Pt site. Furthermore, the surface demonstrates stable physisorption of carbon dioxide (CO 2 ) through weak van der Waals forces, suggesting its potential for co-adsorption reactions. In conclusion, segregation of Pt to the L 10 -MnGa surface creates a promising material. It successfully combines the perpendicular magnetic anisotropy of the MnGa substrate with enhanced surface reactivity, making it a strong candidate for novel spintronic-catalytic applications.