Unravelling the Mechanical and Superconducting Properties in Borophene with Multicentered Bonds

The multicentered bonds present in planar borophene lead to a more complex structure and richer chemical properties. Herein, we use first-principles calculations to investigate the electronic, mechanical, and superconducting properties of various borophene polymorphs, focusing on the newly synthesized β and β13 phases. Notably, in order to balance and optimize the electron filling of the valence bond orbitals, the planar borophene structure is composed of a mixture of triangular lattices and hexagonal holes with multicentered bonding, which further enhances the stability of the structure and possesses a rare polymorphic property. The calculations reveal that the independent phases of borophenes, namely, χ3, β, β12, and β13 exhibit significantly enhanced dynamic stability. Compared with χ3 and β12, β and β13 exhibit a higher ideal shear strength, which is attributed in part to the presence of trimer-like motifs and hexagonal motifs within their lattice. Meanwhile, all of these borophene phases exhibit distinct superconductivity, with the superconducting critical temperature of the later synthesized β and β13 phases reaching 7 K. The significant mechanical and superconducting properties exhibited by these independent borophene structures confer them broader application prospects in electrode materials and energy storage materials.