C1 vacancy in pentagraphene*

Pentagraphene (PG), a two-dimensional allotrope of carbon with only five-membered rings, was recently predicted to exhibit exciting electronic and thermal properties with possible implications in nanoelectronics. However, its potential properties arising from defects have not been explored yet. Here, we explore the C1 vacancy in PG using first-principles density functional calculations. This defect introduces four midgap levels indicating the possibility of studying the charge states. The charged defect is amphoteric with deep donor and deep acceptor levels. Introducing the vacancy in the sheet renders it inherently ferromagnetic (FM) with a magnetic moment of 4 μ_B. Upon further investigating spin polarization in PG, three possible unique magnetic configurations are found to exist: FM, anti-ferromagnetic (AFM)−dominant, and quenched-AFM. The energy differences between the FM and the AFM states are on an average ~2 meV/atom, indicating that reversible spin manipulation through thermal energy is possible.