Tunnel barrier engineering of spin-polarized mild band gap vertical ternary heterostructures

The atomic and electronic structures and properties of advanced 2D ternary vertical spin-polarized semiconducting heterostructures based on mild band gap graphitic carbon nitride g-C₃N₄ and ferromagnetic single-layer CrI₃ fragments, namely CrI₃/g-C₃N₄/CrI₃ and g-C₃N₄/CrI₃/g-C₃N₄, were proposed and examined using the ab initio GGA PBE PBC technique. Both possible ferromagnetic (FM) and antiferromagnetic (AFM) spin ordering configurations of CrI₃/g-C₃N₄/CrI₃ were considered and found to be energetically degenerated, being significantly different in the density of states. Electronic structure calculations revealed that weak van der Waals interactions between the fragments are responsible for the main features of the atomic and electronic structures of both the types of heterostructures. The combination of flat valence and conduction bands and conductivity channels localized at spin-polarized semiconducting CrI₃ fragments makes proposed heterostructures as magnetic tunnel junctions for spin- and photo-related applications such as spintronics, magnetoresistive random-access memory, photocatalysis, and as elements for highly efficient spin-polarized photovoltaic nanodevices.