Investigation of strain and doping on the electronic properties of single layers of C6N6 and C6N8: a first principles study

Abstract

In this work, by performing first-principles calculations, we explore the effects of various atom impurities on the electronic and magnetic properties of single layers of C6N6 and C6N8. Our results indicate that atom doping may significantly modify the electronic properties. Surprisingly, doping Cr into a holey site of C6N6 monolayer was found to exhibit a narrow band gap of 125 meV upon compression strain, considering the spin–orbit coupling effect. Also, a C atom doped in C6N8 monolayer shows semi-metal nature under compression strains larger than -2%. Our results propose that Mg or Ca doped into strained C6N6 may exhibit small band gaps in the range of 10–30 meV. In addition, a magnetic-to-nonmagnetic phase transition can occur under large tensile strains in the Ca doped C6N8 monolayer. Our results highlight the electronic properties and magnetism of C6N6 and C6N8 monolayers. Our results show that the electronic properties can be effectively modified by atom doping and mechanical strain, thereby offering new possibilities to tailor the electronic and magnetic properties of C6N6 and C6N8 carbon nitride monolayers.