The development of two dimensional group IV chalcogenides, blocks for van der Waals heterostructures

In this work, we introduce a series of two dimensional (2D) group IV chalcogenides (AX)₂ with the building block X-A-A-X (A = Si, Ge, Sn, and Pb, and X = Se and Te) on the basis of ab initio calculations. The analysis of energy evaluation, lattice vibration as well as the chemical bonding demonstrate the good stability of these 2D materials. Furthermore, the pictures for the chemical bonding and electronic features of the 2D (AX)₂ are drawn. Their narrow gapped semiconducting nature is unraveled. Especially, strong interactions between the electrons and phonons as well as the topological insulating nature in (SiTe)₂ are observed. The present results indicate that such remarkable artificial 2D (AX)₂ are building blocks for van der Waals heterostructure engineering, which shows potential applications in nanoscaled electronics and optoelectronics.