Effects of pressure on structural, mechanical, and electronic properties of chalcopyrite compound CuAlS2

First-principles method is performed to investigate the structural, electronic, elastic and mechanical characteristics of the tetragonal CuAlS2 in the pressure range from 0 to 10 GPa. The results indicated that both the lattice constant and cell volume decrease with the increase of pressure, which are matched well with available previous values. The pressure has a more significant influence on the c direction than the a and b direction. The obtained elastic constants reveal the tetragonal CuAlS2 is mechanically stable between 0 and 10 GPa. The bulk, shear, and Young’s modulus are evaluated by Voigt-Reuss-Hill approximation. All these elastic moduli exhibit a monotonic feature as a function of pressure. The Poisson’s ratio, Pugh’s criterion, and Cauchy pressure indicate that ternary chalcopyrite semiconductor CuAlS2 is ductile against pressure. Meanwhile, the analysis of the electronic structures reveals that the states near the valence band top are derived from Cu 3d and S 3p orbitals, and the lowest conduction band is composed of Al 3p and S 3p orbitals. We expect that the findings predicted the physical properties of this compound will promote future experimental studies on CuAlS2.