The spin-polarized linear muffin-tin orbital method was used to calculate the electronic structure of ’ phases, Fe4Z, where Z was H, C or N. The chemical bonding effects of the interstitial Z atom were investigated, and the results indicated that insertion of the Z atom changed not only the Fe-Fe interaction, but also the Fe-Z interaction. The latter depended upon the chemical properties of the Z atom. On the basis of the results, it was concluded that the interstitial chemical bonding effect in Fe4Z was determined mainly by the covalent nature of the Fe-Z bonds.

Y.Kong, R.Zhou, F.Li: Physical Review B, 1996, 54[8], 5460-5