Negative differential resistance and transport regularity in aromatic cyclo[n]carbon-based (n = 4k + 2) molecular devices

Abstract

Cyclo[18]carbon (C₁₈), which has been successfully synthesized and extensively studied, exhibits unique electronic transport properties. Cyclo[n]carbons (C_n, n = 4k + 2), sharing a similar π-electron conjugation with C₁₈, potentially demonstrate comparable or even superior transport characteristics. In this study, three C_n devices with different types of electrodes have been investigated using density functional theory combined with the nonequilibrium Green's function. Our findings reveal that the devices with large-diameter carbon rings tend to exhibit the negative differential resistance (NDR) effect. The magnitude, position, and number of NDR peaks are remarkably affected by the number of carbon atoms and the type of electrode. However, the NDR effect does not appear in devices with odd-numbered rings. This study sheds light on the remarkable electronic transport properties of C_n molecules and offers valuable insights for the development of advanced carbon-based molecular devices.