The new antiferromagnetic semiconductor : Predicting from first-principle theory

The electronic and magnetic properties of the calcium ferrite-type NaMn 2 O 4 were studied using the full-potential linearized augmented plane wave method. The results indicate that an antiferromagnetic ground state is energetically favored over ferromagnetic and ferrimagnetic state. NaMn 2 O 4 in the antiferromagnetic configuration is semiconductor both from the GGA and GGA+U calculations. The spin magnetic moments and density of states of Mn atoms show that Mn 3 + / Mn 4 + charge ordering presents, in agreement with the experimental observation. Accompanying the charge and antiferromagnetic spin orderings, an orbital ordering exists in NaMn 2 O 4 due to the Jahn-Teller effect of Mn 3 + ions.