Strong interlayer interaction in two-dimensional layered PtTe2

We investigate the interlayer interaction in the two-dimensional (2D) PtTe2 by using first-principles calculations. As the number of layers increases, the band gap decreases to 0 ​eV, resulting in a transition from semiconductor to semi-metal. The band gap is decreased due to the splitting of the band, causing the anti-bonding state to move toward the Fermi level. Our research exhibits that there is an interaction between adjacent layers, which does not exist in most multilayer 2D materials and is stronger than the van der Waals (vdW) interaction. We use covalent-like Te…Te bond to represent this interaction. Consequently, we reveal that this interlayer interaction originated in the pz orbitals of Te atoms in adjacent layers.