How do electronic properties of conventional III–V semiconductors hold for the III–V boron bismuth BBi compound?

We have performed ab‐initio self‐consistent calculations using the full potential linear augmented plane wave method to investigate the structural and the electronic properties of the boron bismuth III–V compound BBi. Our calculations provide the first available information about the structural and electronic ground‐state properties of BBi. Total energy calculations of the cubic zinc‐blende, wurtzite, rock‐salt, cesium chloride and orthorhombic Cmcm phases are made. The zinc‐blende structure is found to be the ground‐state phase of BBi; within the generalized gradient approximation (local density approximation), we found a lattice constant of 5.529 Å (5.416 Å) and a bulk modulus of 72.20 GPa (86.27 GPa). We found that, contrary to other boron compounds, the band gap of BBi is direct at the Γ point. The relativistic contraction of the 6s orbital of Bi has a strong influence on the bands and bonds of BBi. Consequently, the electronic properties of BBi are shown to differ considerably from those of common group III–V semiconductors (e.g. GaAs); in particular, we found an unusually strong p–p mixing of the valence‐band maximum relative to most of the other III–V compounds. Furthermore, the calculated valence charge density shows an anomalous behavior, characterized by a charge transfer towards the ‘cation' B atom, further illustrating the rich behavior of boron bismuth compounds. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)