Strain modulating half-metallicity of semifluorinated GaN nanosheets

For two-bilayer GaN nanosheets with fluorination on one-side Ga atoms, the band gaps in spin-up and spin-down states as a function of biaxial strain ε. Here ε is defined as ε = (a − a0)/a0, where a0 and a are the lattice constants of systems without and with strain, respectively. The atomic structures with ferromagnetic states (a) in top view and (b) in side view at ε = 0, (c) in side view at ε = +26% are given in the inserts.104