A novel two-dimensional beryllium diphosphide (BeP2) with superconductivity: the first-principles exploration

Abstract

In this study, three stable two-dimensional beryllium diphosphide (2D-BeP₂) structures with the wrinkle and planar monolayers, namely MoS₂-like m-BeP₂ phase (1H-BeP₂), pentagonal 2m-BeP₂ (Penta-BeP₂) and planar mm2-BeP₂ (Planar-BeP₂), have been successfully predicted through the first-principles calculation combined with a global structure search method. The structural stabilities, mechanical properties, electron properties and superconductivities are also systematically investigated. Results indicated that the 2D MoS₂-like 1H-BeP₂ showed higher stability than the Penta- and Planar-BeP₂ structures. The 1H-BeP₂ structure possessed an intrinsic metallic characteristics with the bands crossing the Fermi level. Notably, the Penta-BeP₂ is a typical semiconductor, and the planar-BeP₂ is semi-metal with Dirac corn. Based on the calculation results of the electron properties, phonon properties and electron–phonon coupling (EPC), the layer 1H-BeP₂ sheet is a phonon-mediated superconductor with a critical temperature (T_c) of about 1.32 K.