AlGaP₂: A novel material with remarkable negative Poisson's ratio and excellent photocatalytic performance

This research introduces a two-dimensional compound, AlGaP₂, which retains its structural integrity under both room and elevated temperatures. Investigations into its mechanical characteristics indicate that AlGaP₂ has an exceptionally low Young's modulus in the y -direction, granting it remarkable flexibility. Notably, the material displays a significant negative Poisson’s ratio of −1.80 in the 23.5° direction, ranking it among the highest for two-dimensional auxetic substances. This unique property arises from alterations in bonding characteristics due to charge transfer during tensile stress. Additionally, calculations of its optical properties reveal that AlGaP₂ possesses high optical absorption efficiency and appropriate band-edge positions for water splitting, making it a promising candidate for photocatalytic applications in clean energy generation.