Electronic structure of six phases of C3N4 a theoretical approach

A systematic study of the structural properties and electronic structure of six phases of C3N4 is presented. The phases under study are the beta, alph a, cubic, pseudocubic and two graphitic with different space group. The str uctural analysis shows that only in beta and graphitic phases the N atoms b ehave in a pure sp(2) configuration. In the other phases, alpha, cubic and pseudocubic, the N with its 3 C neighbors form a pyramid. The band structur e for each of the six phases is presented indicating with beta, alpha and c ubic phases have an indirect gap while the pseudocubic and the two graphiti c phases have a direct gap. Also charge density contours are presented and analyzed.