Pivotal role of the B12-core in the structural evolution of B52–B64 clusters

Abstract

An icosahedral B₁₂ cage is a basic building block of various boron allotropes, and it also plays a vital role in augmenting the stability of fullerene-like boron nanoclusters. However, the evolution of compact core–shell structures is still a puzzle. Using a genetic algorithm combined with density functional theory calculations, we have performed a global search for the lowest-energy structures of B_n clusters with n = 52–64, which reveals that bilayer and core–shell motifs frequently alternate as the ground state. Their structural stability is assessed, and the competition mechanism between various patterns is also elucidated. More interestingly, an unprecedented icosahedral B₁₂-core half-covered structure is identified at B₅₈, which bridges the gap between the smallest core–shell B₄@B₄₂ and the complete core–shell B₁₂@B₈₄ cluster. Our findings provide valuable insights into the bonding pattern and growth behavior of medium-sized boron clusters, which facilitate the experimental synthesis of boron nanostructures.