The role of the electrostatic interlayer interaction in SiC/GeC heterostructures

2D SiC and GeC sheets are polar materials with in-plane charge transfer from Si (Ge) to C atoms, and the electrostatic forces play a key role in intra-layer bonding. An interesting question is how the electrostatic interaction between layers, triggered by such charge transfer, plays a role in stabilizing the vertical heterostructures beyond vdW interaction? In this preliminary study, we have investigated the structural stability of 2D SiC/GeC bilayer heterostructure with different stacking and out-of-plane species ordering within the framework of density functional theory. We found that the electrostatic interlayer interaction leads a strong orbital hybridization between layers for the Si-C species ordering systems but a weak orbital hybridization between layers for C-C species ordering systems. Such species ordering dependent feature is also found in stabilizing interlayer distance. The electrostatic forces mainly stabilized the interlayer distance in Si-C ordering and the vdW interaction only make the system attain a lower cohesive energy. vdW interaction, on the other hand, mainly controls the interlayer distance and hybridization in C-C and Si-Ge orderings. Study of the electrostatic effects on the electronic and mechanical properties is undergoing.