Transformation between Different Hybridized Bonding Structures in Two-Dimensional Diamond-Based Materials

Although knowledge about carbon hybrid films comprising both sp(2) and sp(3) bonding structures is of great importance for innovation applications of diamond-based nanostructures, little is known about the mixed hybridization forms in the same two-dimensional material. In this study, the structural properties of two-dimensional diamond nanoflakes (DNFs) are explored using density functional theory (DFT) simulations. The DFT results indicate that phase transformations between different hybridized bonding structures do occur in two-dimensional DNFs. Moreover, the reconstruction process is proposed to take place on the DNF (100) surface only if the direction in which new C-C bonds will be formed is oriented along the crystallographic direction of the principal axis. These outcomes indicate that the stability of DNFs is dependent on both the surface morphology and the principal axis, and mixed hybridization forms of sp(2) and sp(3) bonding structures can coexist in the same two-dimensional diamond-based material.