Electronic Transport of (SiC)n (n = 1–4) Molecular Chains via First-Principles Calculations

The rapid development of miniaturized electronic devices has aroused intense interest in one-dimensional (1D) nanostructures research. Silicon carbide (SiC) owns abundant 1D geometrical structures, but little is known about their electronic transport properties. Hence, we conduct the systematic study of the electronic transport behavior of (SiC)n (n = 1–4) molecular linear chain, based on the density functional theory and nonequilibrium Green’s function formalism. Results reveal that the conductance of SiC chain is highly sensitive to the local atomic rearrangement, and n is also an important factor to affect their transport properties: the longer the SiC chain, the higher localization of the frontier molecular orbitals and the deeper suppression in transmission spectrum which gives the lower equilibrium conductance and the current. Current–voltage curve of SiC chains exhibit nonlinearity, implying their semiconductor characteristics. The rectifying ratios increase with n which reflect their asymmetric built-in structures and unequal coupling to Au surfaces. Additionally, by analyzing their projected densities of states, we find that px and py orbitals from Si and C atoms make a major contribution to electronic transport channel. Our theoretical studies are expected to provide more fundamental and comprehensive information for further research of the SiC linear chains.