Probing the structure and electronic properties of beryllium doped boron clusters: A planar BeB 16 - cluster motif for metallo-borophene.

Beryllium-doped boron clusters display essential similarities to borophene (boron sheet) with a molecular structure characterized by remarkable properties, such as anisotropy, metallicity and high conductivity. Here we have determined low-energy structures of BeB _n ^0/- (n = 10-20) clusters by utilizing CALYPSO searching program and DFT optimization. The results indicated that most ground states of clusters prefer plane or quasi-plane structures by doped Be atom. A novel unexpected fascinating planar BeB ₁₆ ^- cluster with C _2v symmetry is uncovered which possesses robust relative stability. Furthermore, planar BeB ₁₆ ^- offers a possibility to construct metallo-borophene nano-materials. Molecular orbital and chemical bonding analysis reveal the peculiarities of BeB ₁₆ ^- cluster brings forth the aromaticity and the strong interaction of B-B σ-bonds in boron network.