Electronic structure of LiZnN: Interstitial insertion rule

LiZnN, like other Nowotny-Juza filled tetrahedral A^IB^IICV compounds, consists of a B^IICV zinc-blende lattice with the AI atoms filling half of the available tetrahedral interstitial sites. Using band calculations we deduce an ``interstitial insertion rule'' which shows, following an earlier argument of Wood, Zunger, and de Groot, how the electronic structures of such ternary compounds constitute recognizable distortions of those of the underlying zinc-blende B^IICV material. The s,p, and d components of the electronic charge density at the tetrahedral interstitial sites of the zinc-blende structure are shown to play a decisive role in understanding quantitatively these distortions.