First-principles study of the ground state stability of III-V bismuth compounds

摘要

In this letter, full potential linearized augmented plane wave method has been used to shed light on the role of relativistic effects on the stability of the zinc-blend (ZB) and PbO phases of III-V bismuth compounds: BBi, AlBi, GaBi, and InBi. In particular, for the heavier III-V bismuth (InBi), ZB phase is found to be the most stable in the case of non-relativistic calculation. However, the stable phase becomes PbO when relativistic effect is considered. Relativistic effects reduce the structural parameters (lattice parameters and bulk modulus) of III-V bismuth compounds. These effects become important when the atomic number increases. For the non-relativistic approximation, all studied compounds are found to be stable in the ZB structure, however, the relativistic correction induces strong reduction of the total energy difference (DELTA E_(ZB-PbO)). Moreover, the total energy difference between the relativistic and non-relativistic approximations is important for all compounds. The most affected by the relativistic effects is InBi. The origins of these relativistic effects are explained in terms of stabilization (destabilization) of s, and p_(1/2) (p_(3/2) and d) orbital energies.