First-principles calculations of structural, elastic, electronic, and optical properties of CaYP (Y = Cu, Ag) Heusler alloys

Abstract

Our comparative study is carried out on different structural, elastic, electronic, and optical properties of two new half-Heusler CaCuP and CaAgP compounds by using first-principles calculations based on density functional density. The generalized gradient approximation (GGA) is used for studying exchange and correlation effects. The mBJ-GGA approximation is also employed to give a better approximation of the energy bandgap for the two CaCuP and CaAgP compounds. Our two compounds are more stable in cubic structure type I structure and the lattices parameters obtained in good agreement with other available data. The two compounds are mechanically stable, the calculated elastic constants strictly obey the stability criteria with brittle behavior, isotropic, and ionic nature in cubic structure type I. The electronic properties have pointed to a semiconductor behavior for the two compounds and have shown a direct gap Γ→Γ equal to 1.785 eV for CaCuP and 1.621 eV for CaAgP with mBJ-GGA approximation. The study of optical properties with mBJ-GGA approximation as a function of photons energy for a wide range between 0 and 27 eV reveals that the two half-Heusler CaCuP and CaAgP compounds display the maximum reflectivity and absorption in the ultra violet range. © 2024 Elsevier B.V., All rights reserved.