Pressure-induced ferromagnetic half-metallicity in cobaltocene

Abstract

The electronic and magnetic properties in organometallic compound cobaltocene under pressure have been investigated by the first-principles calculations based on the van der Waals density functional theory. At ambient pressure, cobaltocene lies in the paramagnetic state, which is consistent with the experimental measurements. With increasing pressure, the paramagnetic phase evolves into the ferromagnetic semiconducting phase. When pressure exceeds 60 GPa, the closing of gap between valent and conducting bands results in the ferromagnetic half-metallicity in cobaltocene. The formation of the metallic state can be understood in terms of the orientation and hybridization of Co dxz, dyz and C pz orbitals. We also find that the ferromagnetic half-metallicity arises at much lower pressure upon doping rhodocene into cobaltocene. Our results provide a new route to realize the half-metallicity in cobaltocene and similar metallocene compounds.