Effects of rare-earth substitution on the stability and electronic structure of REZnOSb (RE = La–Nd, Sm–Gd) investigated via first-principles calculations

Abstract The structural stability, chemical bonding, Mulliken populations, and charge-density distribution of RE ZnOSb ( RE  = La–Nd, Sm–Gd) were investigated by first-principles calculations. Unit cell parameters calculated by the generalized gradient approximation (GGA) are in better agreement with experimental results than those derived from the local density approximation (LDA). Binding energy comparisons indicate that the structural stability of RE ZnOSb decreases with the increment of the atomic number of the RE , as confirmed by X-ray diffraction (XRD) results. Semimetal or narrow band-gap semiconductor behaviors are found for selected RE ZnOSb. Moreover, chemical bonding analysis shows that there exist considerable polar covalent interactions between the participating atoms. It also reveals that the [ZnSb] layers receive some electrons from the [LaO] layers (donor) as an electrons acceptor and holes transport tunnel. The covalent interactions between the [ZnSb] and [LaO] layers, which are enhanced by 4 f -electrons of the RE , are supposed to improve the electrical transport properties.