Theoretical prediction on the stability, elastic, electronic and optical properties of MAB-phase M4AlB4 compounds (M = Cr, Mo, W)

Abstract

This research employs first-principles calculations to address the challenges presented by processing complexity and low damage tolerance in transition metal borides. The study focuses on designing and investigating MAB phase compounds of M₄AlB₄ (M = Cr, Mo, W). We conduct a comprehensive assessment of the stability, phononic, electronic, elastic, and optical properties of Cr₄AlB₄, Mo₄AlB₄, and W₄AlB₄. The calculated results reveal formation enthalpies of −0.516, −0.490, and −0.336 eV per atom for Cr₄AlB₄, Mo₄AlB₄, and W₄AlB₄, respectively. Notably, W₄AlB₄ emerges as a promising precursor material for MABene synthesis, demonstrating exceptional thermal shock resistance. The dielectric constants ε₁(0) were determined as 126.466, 80.277, and 136.267 for Cr₄AlB₄, Mo₄AlB₄, and W₄AlB₄, respectively. Significantly, W₄AlB₄ exhibits remarkably high reflectivity (>80%) within the wavelength range of 19.84–23.6 nm, making it an ideal candidate for extreme ultraviolet (EUV) reflective coatings. The insights gleaned from this study provide a strong research framework and theoretical guidance for advancing the synthesis of innovative MAB-phase compounds.