Electronic structure of Ge3N4 possible structures

Abstract

Experiments have shown that Ge3N4 is a promising material for application in photodiodes, amplifiers, optic fibers, protective coatings, etc., and several experimental studies have been carried out on this material, however, only one theoretical study has been reported in the literature about β-Ge3N4. In this work we present a systematic study of the structural properties and electronic structure of five possible structures of Ge3N4. The phases under study are the α, β, cubic, pseudocubic, and graphitic. The analysis shows that the hardest is the cubic with a bulk modulus B=232.5 GPa, while the α and β have the same bulk modulus (B=219.8 GPa). The pseudocubic and graphitic phases are the softest with B=147.0 and 61.7 GPa, respectively. The band structure shows that the α, β, cubic, and pseudocubic have an indirect band gap while the graphitic has a direct band gap. Total energy considerations indicate that the β phase is the most stable while the graphitic is the less stable one. Charge density analysis is also included. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 80: 249–257, 2000