Further study on structural and electronic properties of silicon phosphide compounds with 3:4 stoichiometry

Si3N4 has been extensively studied, due to its potential applications in electronic devices. Substitution of N by P results in Si3P4 which is a relatively unknown material. In this study, we carried out further investigation on the structural and electronic properties of Si3P4 using first principles total energy method based on the density functional theory and the generalized gradient approximation. Our calculations show that pseudocubic-Si3P4 is energetically favored. However, the present study based on the generalized gradient approximation predicts that the α phase is more stable than the γ phase which was predicted to be more energetically stable in an earlier study based on the local density approximation. Other properties such as bulk modulus, band structure, of Si3P4 calculated using GGA are consistent with the LDA results.