The diverse electronic properties of C₄N₃ monolayer under biaxial compressive strain: a theoretical study

Because of the observation of half-metallicity in graphitic carbon nitride C₄N₃ (g-C₄N₃), extensive research has recently been focused on this compound. Using density-functional calculations, herein diverse electronic properties of g-C₄N₃ were engineered by applying biaxial compressive strain. The calculated results demonstrate that g-C₄N₃ preserves ferromagnetic half-metallicity when the strain is lower than  −2%, accompanied by a decrease of the half-metallic gap. When the compressive strain ranges from  −5 to  −3%, the compound turns into nonmagnetic metal. By increasing the strain on the end, it becomes a nonmagnetic semiconductor. Further investigations show that all nonmagnetic semiconductors possess a direct band gap with a value of around 1.6 eV. This fact indicates that g-C₄N₃ can be applied in spintronic or photovoltaic fields under a strain environment. (paper)