Multifunctional two-dimensional graphene-like boron nitride allotrope of g-B 3 N 5 : A competitor to g-BN?

The challenge in materials science is to meet the functional requirements in various aspects, where multifunctional materials can greatly expand the scope of applications. Compounds formed by atoms of boron (B) and nitrogen (N) provide a superior platform for exploring multifunctional materials. However, previous studies mainly focused on three-dimensional due to the controversial stability of two-dimensional (2D) structures. Herein, we designed a multifunctional 2D graphene-like boron nitride material with a buckling structure, namely g-B 3 N 5. The stability is comprehensively proved from the aspects of mechanical, thermal, dynamic, and energetic behaviours. Furthermore, we systematically explored its mechanics, electronics, thermal, and optical properties, respectively. Excellent performances are found in g-B 3 N 5, i.e, negative Poisson's ratio, ultra-wide band gap (4.32 eV), low thermal conductivity (21.08 W/mK), and highly tunable photon absorption peak by strain engineering. The multifunctional performance can bring new vitality to the field of BN-phase semiconductors as a strong competitor of g-BN.