Electronic and Topological Analysis for New Phases of Chromium Nitride

다국어 초록 (Multilingual Abstract)

Chromium nitride (CrN) in its NaCl‐type phase has been widely studied through density functional theory (DFT) in order to analyze its electronic properties. By the means of DFT with the Becke's three parameter Lee‐Yang‐Parr (B3LYP) hybrid functional, the same stoichiometry is studied in two unreported hypothetical phases in addition to the nonsynthesized and previously reported zinc‐blende‐type phase. The cohesive energy of every structure is calculated, and the analysis of this quantity indicated that all crystals are stable and that there is an unreported phase more stable than the synthesized one. The calculated electronic dispersion relation and density of electronic states allowed for the determination that these three phases have a conducting behavior. The symmetry of some bands is determined as a result of the crystal field splitting for chromium d states. The topology of the electron density was studied in order to determine its properties at bond critical points (BCPs). The form of the Laplacian of the density and its gradient trajectories allowed to locate ring critical points in these structures. From these calculations, it is concluded that all three phases are ionic crystals. The synthesized NaCl‐type phase is studied in order to compare and confirm the results.
This work studies three hypothetical in addition to one experimental phases of chromium nitride through density functional theory methods. Two of these phases are orthorhombic, a zinc blende phase and the experimental NaCl‐type one. The calculations allow to show the band structure, density of states and topology of electron density for each crystal structure.