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.

Squeezing transfer of light in a two-mode optomechanical system.

The squeezing transfer from a squeezed vacuum injected in one cavity to the output spectrum of the other cavity in an optomechanical system is investigated. By calculating the noise spectrum of the output field, it is found that two squeezing dips appear symmetrically located about the resonant point. Besides the contribution from the destructive interference between the noise fluctuation of the input field and its optomechanically modified one, the major part of the squeezing is transferred from the squeezed vacuum injected in the cavity. Additionally, it is shown that the adverse effects of the environment temperature on the output spectrum can be strongly suppressed by the injected squeezed field. This study can be useful in quantum communications via the optomechanical interface.