Site selective Ag doping in Cu3N and its consequences on structural and electronic properties: A DFT study

Abstract

The effects of Ag doping on structural, thermodynamical and electronic properties of Cu3N are investigated using density functional calculations. The doped atom is introduced into the host lattice in two possible ways: filling the vacant interstitial site (interstitial doping) and substituting Cu (substitutional doping). Though volume of the lattice expands in both the cases, the variation of lattice parameters is strictly dependent on impurity sites in case of substitutional doping whereas for interstitial doping, no such dependency is noticed. Similar to their parent compound, both the doped systems are thermodynamically metastable. A thorough investigation of the electronic structure successfully demonstrates host-impurity covalent bonding mechanism and formation of energy bands out of these interactions. The results predict an indirect band gap semiconducting nature for the substitutional doped system, however with a reduced energy gap compared to the pure compound. On the other hand, interstitial Ag doping in Cu3N induces semimetallic behavior.