First Principles Study Of Rare Earth Element Doped Copper Nitride

As a new material used for optical storage devices and high-speed integrated circuits, copper nitride(Cu3N) has achieved considerable attention. Cu3 N is a metastable semiconductor having high resistivity and low decomposition temperature, Cu3 N has a cubic anti-ReO3 crystal structure in which the nitrogen atoms are located at the corners of the cell forming collinear bonds with the copper atoms occupying the middle of the edges. This structure is peculiar because the copper atoms do not occupy the face-centered cubic close-packing sites. As a result, this crystal structure has many vacant interstitial sites. The properties of Cu3 N will be different obviously when interposed by other atoms.The central point of this paper is that we investigate the structural, electronic, elastic and optical properties of Cu3 N and Cu3NM(M=Sc, Y, La and the other lanthanide series metal) compounds by using first-principles density functional theory(DFT) implemented in the WIEN2 K code. The physical properties of the Cu3 N and Cu3 NM compunds have been obtained by using the lattice constant obtained after optimization. In order to analyze the different influence on Cu3 N doped by the M atom belonging to the same group or the 4f orbital electron increasing, this paper study the Cu3NM1(M1=Sc, Y and La) and Cu3NM2(M2=lanthanide series metal) respectively. The results show that:(1) The lattice parameters increased after Cu3 N doped by M1(M1=Sc, Y and La) atoms. The results of the electical property show that Cu3 N is a semiconductor as well as Cu-3d and N-2p has strong hybridizations. However when doped by M1 atoms, Cu3 N becomes a conductor and has a strong hybridizations between M1-d and Cu-3d. The calculated bulk moduli and elastic constants show that all the Cu3 N and Cu3NM1 compunds are mechanically stable. The results of the optical property show that M1 atoms have a great influence on the optical properties of the Cu3 N. The heats of formation indicate that it is more easier to get Cu3NM1 in the lab, the M1-doping makes Cu3 N more stable.(2) The M2(M2=lanthanide series metal) atoms doing have a big influence on the physical property of Cu3 N. The results of lattice parameters shows that an inserted M2 atom at the center of the cube leads to a volume expansion, and with the increase of the number of 4f orbital electron, the(3) lattice parameters have a downward trend. The heats of formation has a irregual change with the increasing number of electrons in the 4f orbitals. The results of the DOS and Band structure show Cu3NM2 compounds have metallic behavior. Compared with Cu3 N, the absorption edge of Cu3NM1 shifts blue obviously.