Structural and Elastic Properties of Antimony Triiodide from First-Principles Calculations

First principles calculations are performed to investigate the structural and elastic properties of SbI3 based on density functional theory for two space groups: trigonal R-3 and monoclinic P21/c. The calculated equilibrium structural parameters agree well with the experimental data. The enthalpy calculations confirm that the trigonal R-3 structure of SbI3 is the most stable structure at zero pressure. For R-3 structure, the obtained bulk, shear, and Youngs modulus are 28.1, 15.2 and 38.6 GPa, respectively. The calculated Debye temperature is 197 K. SbI3 presents large elastic anisotropy, stronger compressibility and better ductility at 0 GPa.