Self-interaction correction for band structure calculation based on local density approximation of iron nitrides

Abstract

The band theory based on the conventional local density approximation (LDA) has not given a quantitative explanation of the mechanism of the giant magnetization of α″-Fe 16N 2 thin film. In this paper, the self-interaction correction (SIC) is applied to the LDA band calculation of α″-Fe 16N 2. The electronic structure is calculated by the self-consistent linearized augmented plane wave (LAPW) method. It can be concluded that the influence of the SIC for α″-Fe 16N 2 is large, although the calculated electronic structures of 3d transition metals and γ′-Fe 4N are little affected by the SIC. The charge density distribution of α″-Fe 16N 2 is uniformly broadened. It appears that the distribution for some sites of Fe atoms in α″-Fe 16N 2 is different from that of bcc Fe atoms. However, the SIC has little effect on the total magnetic moment. The SIC is unable to explain the giant magnetic moment. It seems that the orbits of iron nitride are probably metallic bond-like, whose orbit is Bloch function-like, although the localization of some sites of Fe atoms of α″-Fe 16N 2 results in more influence than that of γ′-Fe 4N.