First-Principles Prediction of Mechanical, Electrical, and Optical Properties in Borates MBO3 (M = Sc, Al, Ga, Ti)

To comprehensively explore the mechanical, electrical, thermal, and optical properties of the MBO3 compound, this work utilizes first-principles calculation methods to conduct computational predictions. The lattice constants, formation energies, and cohesive energies of these compounds were calculated, which illustrated the rationality and accuracy of the method. Notably, the approach achieved less than 2% deviation from experimental references, surpassing the errors typical of conventional models. The elastic constant and elastic modulus are calculated. On this basis, the anisotropy index and the anisotropy factor were calculated. At the same time, the 3D surface structures of the bulk modulus, shear modulus, and Young's modulus of the four compounds were also plotted. The 2D projection structure on the (100), (010), and (001) planes were drawn, These visualizations provide the first comprehensive atlas for anisotropic engineering of MBO₃ systems. Then, the electronic structures and DOS of them were calculated, and found that ScBO3 and GaBO3 were p-type semiconductors with direct bandgaps, and AlBO3 was p-type semiconductors with indirect bandgaps, while TiBO3 was n-type semiconductors with indirect bandgaps. In addition, the optical properties of them were calculated. Finally, their Debye temperature and minimum thermal conductivity were calculated.