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

• Published in: Physical chemistry chemical physics : PCCP Vol. 23; no. 22; pp. 12834 - 12841
• Main Authors: Li, Hengtao, Wang, Hongyan, Yan, Luo, Li, Xiumei, Chen, Yuanzheng, Wang, Hui
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 09.06.2021
• Subjects: Banded structure; Beryllium; Dimensional stability; Electrons; First principles; Mathematical analysis; Mechanical properties; Molybdenum disulfide; Phonons; Superconductivity
• ISSN: 1463-9076; 1463-9084; 1463-9084
• DOI: 10.1039/d0cp05230b

In this study, three stable two-dimensional beryllium diphosphide (2D-BeP 2 ) structures with the wrinkle and planar monolayers, namely MoS 2 -like 6&cmb.macr; m -BeP 2 phase (1H-BeP 2 ), pentagonal 4&cmb.macr;2 m -BeP 2 (Penta-BeP 2 ) and planar mm 2-BeP 2 (Planar-BeP 2 ), 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 MoS 2 -like 1H-BeP 2 showed higher stability than the Penta- and Planar-BeP 2 structures. The 1H-BeP 2 structure possessed an intrinsic metallic characteristics with the bands crossing the Fermi level. Notably, the Penta-BeP 2 is a typical semiconductor, and the planar-BeP 2 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-BeP 2 sheet is a phonon-mediated superconductor with a critical temperature ( T c ) of about 1.32 K. The 1H-BeP 2 monolayer is a moderate-coupling superconductor with the total electron-phonon coupling coefficient λ of 0.427 and the logarithmic average frequency ( ω log ) of ∼221.