First-principles study on the atomic structure of two-dimensional molybdenum boride

Abstract

Abstract In recent years two-dimensional (2D) materials have attracted extensive research due to their excellent physical properties in thermoelectricity and superconductivity, etc. This interest led to both a new wave of research on known 2D materials, such as transition metal nitrides (MXene), and the discovery of many new 2D materials. Recently, the 2D metal borides Mo4/3B2−x with ordered metal vacancies were successfully synthesized. However, variable atomic structures were experimentally observed in the specimen, suggesting that more than one structure exists in this 2D material. Therefore, in this work, the stabilities of molybdenum boride with different Mo content are examined employing first-principles calculation based on the density functional theory. The binding energies of different molybdenum boride models are calculated and analyzed, and the effect of the Mo content on their stability was investigated. The chemical bonding properties are also analyzed via electron localization functions, which further answer why the experimentally synthesized molybdenum borides would have different atomic structures.