Structural and electronic transport properties of a SiC chain encapsulated inside a SiC nanotube: first-principles study

Ab initio study revealing remarkable oscillatory effects and negative differential resistance in the molecular device of silicon carbide chains

Inspired by the requirements of miniaturization and multifunction of molecular devices, we investigate the quantum transport properties of three unique molecular devices with silicon carbide chains bridging gold electrodes by an ab initio approach. The pronounced quantum effects, including the oscillation of charge, conductance, and current, together with the negative differential resistance (NDR), have been observed simultaneously over a wide region in the double-chain device. It changes the regular situation that these two effects usually emerge in single-chain systems at the same time. Inspections of the visible differences in the transport behaviors relevant to length and bias between the three devices further evidence that the interchain interaction and molecule-electrode coupling are decisive factors for achieving the quantum effects of oscillation and NDR. These two factors can improve electronic transport capability through enhancing transmission, strengthening the delocalization of frontier molecular orbitals, and reducing potential barriers. Our results not only lay a solid foundation for the application of silicon carbide chains in the miniaturized and multifunctional molecular devices with good performance, but also provide an efficient way to the continuing search for materials with multiple controllable quantum effects in nanoelectronics.

Ligand-Core Interaction in Ligand-Protected Ag25(XR)18 (X= S, Se, Te) Superatoms. Evaluation of Anchor Atom Role via Relativistic DFT Calculations

The isostructural and isoelectronic silver [Ag25(SR)18]- (R=Ligand) cluster to [Au25(SR)18]- gold clusters allows to further understand the fundamental similarities between Au and Ag, at the ultrasmall nanoscale (< 2 nm)...

Achieved negative differential resistance behavior of Si/B-substituted into a C6 chain sandwiched between capped carbon nanotube junctions

Electronic transport properties of a pristine C₆ chain and Si/B-substituted into the C₆ chain sandwiched between two (5, 5) capped carbon nanotube electrodes were investigated through first-principles calculations based on non-equilibrium Green's functions (NEGF) conjugated with density functional theory (DFT). Si and B substitutions will affect the I–V curve of a pristine C₆ chain. In the I–V characteristics, multi negative differential resistance (NDR) with large peak to valley ratio (PVR) and rectifying actions were observed. The NDR behavior originates from the joining and moving of conduction orbitals inside and outside of the bias window at a certain bias voltage. Furthermore, the assessment of transmission coefficient and distribution of molecular orbitals reveals that the rectifying performance is the result of the asymmetric distribution of the frontier molecular orbitals in the central region and their coupling with the electrodes. Multi NDR behavior of B substitution under very low bias voltage is a unique property of our proposed devices. Moreover, the CNT|C–(B–C)₂–C|CNT molecular device shows a high PVR up to 31.8, which demonstrates that the proposed devices can be useful for molecular switching in nanoelectronic devices.

Multi negative differential resistance (NDR) with large peak to valley ratio (PVR) and rectifying actions were observed for a CNT|C–(B–C)₂–C|CNT molecular device.