Electronic and Magnetic Properties of Highly Correlated Half Metallic Layered Sr2CoO4 Cobaltate Using mBJ Exchange Potential

Abstract

We have investigated the electronic and magnetic response of layered Sr2CoO4 (SCO) using Tran-Blaha modified Becke-Johnson potential (mBJ) within the density functional theory. The optimized lattice parameters were determined for the ground state energy of ferromagnetic SCO. Present calculations reveal a peculiar half metallic character with an indirect band gap of 1 eV in the minority state. The magnetic moments on Co and O atoms are observed to be antialligned with each other, resulting to a magnetic moment of 1 µB/f.u. Electronic occupancies for the various orbitals of Co and O atoms have been deduced, suggesting the Co-3 dxy and O2- pz orbitals to be majorly possessing magnetic moments in the SCO system. Hybridisation between different orbitals and their contribution in forming the Fermi surfaces (FSs) are discussed. It is revealed that in half-metallic ferromagnetic SCO, FS structures are formed due to majority spin Co-\({3d}_{{x^{2}-y}^{2}}\) and Co-\({3d}_{z^{2}}\) orbitals hybridised with O-2p orbitals. It is inferred that majority spin Co-\({3d}_{{x^{2}-y}^{2}}\) (dominantly) and pz electrons of O atoms are responsible for the conduction mechanism. Present results provide the usefulness of mBJ approach in deducing the electronic and magnetic properties of layered SCO. Deduction of orbital magnetic moment for cobaltates-like systems would be very crucial to further understand its magnetic properties.