Regulation on the negative differential resistance and spin-splitting effects with halogen and oxygen-doping for α-2-graphyne nanoribbons

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With the continuous improvement on the size requirements of integrated circuit fabrication, the research on the miniaturization of electronic device is favored by more and more scientists. This paper systematically investigated the edge modifications on the electronic band structure of α-2-graphyne and electronic transport characteristics of its devices by employing the density functional theory combined with non-equilibrium Green's functions. From the research results of the band structures with halogens or oxygenated group doping, when the various elements doping within the antiferromagnetic configuration have been applied in α-2-graphyne, the materials exhibit unique semiconductor properties. In particular, the periodic structure of α-2-graphyne with the O-doping exhibits relatively complex band structures near the Fermi level. We can find that the electronic devices with F, Cl, O, OH doping show obvious negative differential resistance (NDR) and spin filtering effects. Among them, the NDR effect of the device with O doping (M4) shows particularly significant feature, and its peak-to-valley ratio within the antiparallel case is as high as 136. However, the peak-to-valley ratio reaches 128 within the antiferromagnetism configuration. In addition, we further dissect the intrinsic physical mechanism of the NDR effect by calculating the transmission spectra and local density of states within the parallel and antiparallel cases. At the same time, the spin filtering efficiency of the device reaches high as 84% at an applied voltage of -0.4V within the parallel case and 79% at -1.6V within antiparallel case. By analyzing the electron transport paths of the M4, we can clearly understand the intrinsic mechanism of the spin-filtering properties for the devices based on the α-2-graphyne nanotibbons. This research will have obvious application value in the research of hot areas such as novel logic devices, integrated circuits and micro/ nano-electronic machines.