Structures and Electronic Properties of the Bi-Sb Superlattice Nanowires and Core-Shell Structural Bi/Sb Nanowires

We systematically study the structural and electronic properties of the Bi-Sb superlattice nanowires and core-shell structural Bi/Sb nanowires by first-principles calculations. The relaxed structures of these heterostructural nanowires are first obtained and found to be similar to those of homogeneous Bi nanowires. For the Bi-Sb superlattice nanowires, band lineups of Bi and Sb zones result in multiple quantum wells, where specific states at the band edges and in band continua are confined. The confined electrons (holes) become more localized if the width of the barrier is larger. For the core-shell structural Bi/Sb nanowires, the electronic properties show dependence on the size, the atom type of core, and the chemical composition. Meanwhile, the valence bands are less affected by the chemical composition, while the conduction bands depend on it. These findings might have important implications for understanding the structural and electronic properties of the heterostructural nanowires and further utilizing them as the potential thermoelectric materials.