First-principles study on the electronic, transport, optical and mechanical properties of cubic boron phosphide

This study employs density functional theory (DFT) to investigate the structural, electronic, transport, optical, and mechanical properties of cubic boron phosphide (c-BP), intending to elucidate its structure-property relationships. The findings reveal that c-BP exhibits an indirect bandgap of 1.93 eV. The valence band maximum (VBM) shows triple degeneracy and pronounced dispersion, resulting in the formation of light-hole bands that provide additional transport channels for holes. A notably high hole mobility of 888.34 cm²·V⁻¹·s⁻¹ is achieved, demonstrating excellent p-type transport characteristics. Furthermore, c-BP possesses very low dielectric loss, broad optical transparency, and mechanical properties characterized by high stiffness and brittleness. This research not only deepens the mechanistic understanding of c-BP's multifunctional behavior but also provides theoretical underpinnings for the design of advanced semiconductor devices.

All calculations were performed within the density functional theory (DFT) framework implemented in the CASTEP code, employing norm-conserving pseudopotentials. Structural relaxation used the GGA-PW91 functional, while electronic and optical properties were computed with the HSE06 hybrid functional.