The structural, elastic and electronic properties of BiI3: First-principles calculations

The structural, elastic and electronic properties of BiI3 are investigated using the first-principles pseudopotential calculations within the framework of density functional theory. The calculated equilibrium structural parameters agree well with the experimental values. The results show that rhombohedral R-3 structure is low enthalpy structure at zero pressure. R-3 structure will transform into SbI3-type structure (space group P21/c) at about 7.0 GPa. At zero pressure, BiI3 with R-3 symmetry meets the mechanical stability criteria, but BiI3 with P-31 m symmetry is an unstable one mechanically. For R-3 structure, the obtained bulk, shear, and Young’s moduli are 25.6, 15.3 and 38.3 GPa, respectively. BiI3 presents large elastic anisotropy. Debye temperature of R-3 structure calculated is 181 K. The metallization pressure of R-3 structure is about 133 GPa and that of predicted high pressure phase P21/c structure is about 61 GPa, indicating BiI3’s potential application as a nuclear radiation detector under high pressure environment.