| Abstract
| - We performed an unbiased search for low-energy structures of medium-sized neutral Sin and Gen clusters (n = 25−33) using a genetic algorithm (GA) coupled with tight-binding interatomic potentials. Structural candidates obtained from our GA search were further optimized by first-principles calculations using density functional theory (DFT). Our approach reproduces well the lowest-energy structures of Sin and Gen clusters of n = 25−29 compared to previous studies, showing the accuracy and reliability of our approach. In the present study, we pay more attention to determine low-lying isomers of Sin and Gen (n = 29−33) and study the growth patterns of these clusters. The B3LYP calculations suggest that the growth pattern of Sin (n = 25−33) clusters undergoes a transition from prolate to cage at n = 31, while this transition appears at n = 26 from the PBE-calculated results. In the size range of 25−33, the corresponding Gen clusters hold the prolate growth pattern. The relative stabilities and different structural motifs of Sin and Gen (n = 25−33) clusters were studied, and the changes of small cluster structures, when acting as building blocks of large clusters, were also discussed.
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