Structural and electronic properties of Si3P4

Abstract

Structural and electronic properties of Si3P4 were investigated using first-principles total-energy method based on density-functional theory and the local-density approximation (LDA). It was found that pseudocubic-Si3P4 is energetically favored relative to other phases of Si3P4 considered in this study. All phases of Si3P4 have low bulk moduli, with the γ phase being the hardest (110 GPa). Furthermore, band-structure and density-of-states calculations reveal that α, β1, pseudocubic, and graphitic phases of Si3P4 are semiconducting while β2, cubic, and γ phases are metallic within LDA. Correction of LDA energy band gap by a more accurate method will likely result in Si3P4 being a narrow gap semiconductor. The structural and electronic properties of Si3P4 are compared with those of similar compounds, i.e., C3N4, Si3N4, Ge3N4, and C 3P4.