Synergetic effects of combining TM single- and double-atom catalysts embedded in C2N on inducing half-metallicity: DFT study

Designing 2D-materials that exhibit half-metallic properties is crucially important in spintronic devices that are used in low-power high-density logic circuits. The large pores in the C2N morphology can stably accommodate various configurations of transition-metal (TM) atoms that can lead to ferromagnetic (FMC) and anti-ferromagnetic coupling interactions among them, and thus paving the way for achieving half-metallic characteristics. In the present study, we use manganese ‘Mn’ as a promising catalyst and the spin-polarized density-functional theory to search for suitable configurations of metal atoms that yield half-metallicity. Test samples comprised of single-atom catalyst (SAC) and double-atom catalyst (DAC) of Mn embedded in a C2N sample of size 2 × 2 primitive cells as well as their combinations in neighboring large pores (i.e. SAC–SAC, SAC–DAC, and DAC–DAC). Tests were extended to screen many other TM catalysts and the results showed the existence of half metallicity in just five cases: (a) C2N:Mn (DAC, SAC–SAC, and SAC–DAC); (b) C2N:Fe (DAC); and (c) C2N:Ni (SAC–DAC). Our results further showed the origins of half-metallicity to be attributed to FMC interactions between the catalysts with the six mirror images, formed by the periodic-boundary conditions. The FMC interaction is found to have strength of about 20 meV and critical length scale up to about ∼21–29 Å, dependent on both the type of magnetic impurity and the synergetic effects. The potential relevance of half-metallicity to spintronic device application is discussed. Our theoretical results have been benchmarked to the available data in literature and they were found to be in good agreements.