Density functional investigation of spin polarization in bulk and thin films of nitrogen intercalated Cu3N

Abstract

Abstract:It has been reported theoretically that the intercalation of nitrogen in the voids of the rather open cubic structure of bulk Cu 3 N build up a magnetic structure. In an extended effort to study this system, we have investigated spin polarization in bulk and thin films of nitrogen intercalated Cu 3 N (Cu 3 N 2 ) structure by means of first-principles calculations based on Kohn-Sham density functional theory and ultrasoft pseudopotentials technique. Contrary to the previous study, the results show that after an accurate structural relaxation of the system, magnetism in the bulk structure vanishes. This effect is due to the migration of the intercalated nitrogen atom from the body center of the cell to the nearness of one of the cell faces. Similar study for the thin films of 5, 7, 9 and 11 2 monolayers thickness was performed and it was found that initial relaxation of structures with 7 and 11 monolayers show a net magnetic moment of 2.6 µ B . By a more extended survey of the energy surfaces, the film with 7 monolayers loses its magnetic moment similar to the bulk structure but the film with 11 monolayers maintains its magnetic moment. It is possibly a new quantum size effect that keeps the intercalated nitrogen atom of the middlemost cell at the body center site. Electron density map of this film clearly confirms the spin polarization upon the intercalated atom.

Systematic study of room-temperature ferromagnetism and the optical response of Zn1−xTMxS/Se (TM = Mn, Fe, Co, Ni) ferromagnets: first-principle approach

“…As we know that bulk characteristics are significantly altered as the material dimensions are reduced to a surface/interface, the knowledge of the bulk properties is crucial to truly comprehending the surface/interface properties, due to which the studied alloys may find spintronic applications. A large amount of literature exists that elucidates the importance of bulk properties in the study of the interface phenomena [34][35][36][37]. In the present study, we report systematically calculated structural, magnetic and optical properties of Zn 1−x TM x S/Se (TM = Mn, Fe, Co, Ni and x = 6.25%).…”