First-principles assessment of the structural, phase transition, electronic, elastic and thermal properties of the semiconductor alloys AlSb1–xBix (x = 0, 0.25, 0.5, 0.75, 1)

In this work, an ab-initio assessment of the structural, phase transition, electronic, elastic and thermal properties of the semiconductor alloys AlSb1–xBix (x = 0, 0.25, 0.5, 0.75, 1) was performed. The structural and elastic properties were analyzed using the Wu–Cohen generalized gradient approximation (WC-GGA), revealing that the zinc blende structure is energetically favored over the wurtzite structure. Phase transitions from zinc blende to NaCl and CsCl phases were identified at pressures ranging from 2.18 to 9.96 GPa, as determined using the Gibbs2 code. Electronic properties, calculated using the modified Becke–Johnson (mBJ) potential, indicated direct band gaps (Γ → Γ) for all compositions except AlSb, which exhibited an indirect band gap (Γ → X), suggesting potential optoelectronic applications. Thermal properties, including specific heat, entropy, and thermal expansion, were also investigated, showing consistent trends with increasing temperature. Moreover, the elastic properties revealed that increasing the bismuth (Bi) content generally led to reduced stiffness (lower shear and Young’s moduli), decreased hardness, increased brittleness, and reduced covalent bonding. However, a notable exception was observed at x = 0.75 where enhanced ductility was found; making this composition particularly interesting for balancing elastic properties. The results were compared with existing data for similar materials, providing a comprehensive theoretical foundation for understanding the multifaceted properties of AlSb₁₋ₓBiₓ alloys and their potential for technological applications. Graphical abstract