Structural reciprocity effect in binary silicon–bismuth clusters

Abstract

It is shown by density functional theory using doubly polarized basis sets that the lower energy structures of silicon–bismuth clusters Bi 4Si 2 and Bi 2Si 4 have the same overall geometry and symmetry and can be formally obtained from each other by mutual substitution and optimization or by direct Bi-substitution to the corresponding neutral Si 6 cluster. Such ‘structural reciprocity’, which is attributed to the fluxionality of Si 6 cluster and the similarity of Bi and Si electronegativities, can be generally true for other pairs of Bi–Si clusters to a lesser degree, and could be remotely related with the metal–semiconductor transition in Bi–Si alloys.