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Encouraged by the successful fabrication of C60‐GNR (GNR=graphene nanoribbon) single‐molecule transistors in experiments, four Fe‐containing derived double‐layered devices of Fe@C60‐GNR are designed by employing different electrode linkages and their transport properties are investigated by using density functional theory (DFT) and nonequilibrium Green's function (NEGF) methods. Regardless of electrode connection, all these devices give rise to a smaller negative differential resistance (NDR) peak at V=0.2 and a higher peak at 1.2 V, suggesting their stable maneuverability as molecular devices and good candidates for developing on(off)‐off(on)‐on(off) current switches. The macroscopic NDR performance depends on the delocalization character and the crossing mechanism of the frontier orbitals. The peak‐to‐valley current ratios (Rmax) range from 454 to 2737, determined by the electrode linkage. Such a large Rmax‐value is necessary for developing dynamic random‐access memory (DRAM) cells. Encapsulating the Fe atom inside C60 not only improves the conductivity but also introduces the spin‐polarized transport property. The spin‐filtering efficiency (SFE) of almost all devices oscillates up and down in response to the bias voltage, indicating the possibility of designing on(off)‐off(on)‐on(off) spin switches and up‐down spin switches. All these fascinating properties provide an important clue for designing similar molecular devices with multiple functions by trapping magnetic transition metal atoms inside fullerenes. [ABSTRACT FROM AUTHOR]

Encouraged by the promising performance of C60-graphene single-molecule transistors observed in experiments, two types of Fen/C60-GNR (n = 2 and 4 and GNR = graphene nanoribbon) molecules with Fe atoms sandwiched between the upper and lower GNR layers were designed and their electronic and transport properties were investigated by employing density functional theory (DFT) and nonequilibrium Green's function (NEGF) methods. Adding the Fe atoms induces high spin magnetism in the systems. Within the considered bias, almost all Fe2/C60-GNR devices generate double NDR peaks, and some of the Fen/C60-GNR devices (n = 2 and 4) possess a large peak-to-valley current ratio R = Ipeak/Ivalley (>400), implying potential applications in developing on–off–on/off–on–off current switches. The NDR character originates from the crossing of the frontier molecular orbitals. In addition, these systems show distinct spin-polarized transport characteristics, with up-spin channels displaying higher conductivity than down-spin pathways. The spin filter efficiency (SFE) oscillates up and down as bias is scanned for almost all devices, suggesting the possibility of designing on–off–on/off–on–off current switches as well as up–down spin switches. All these findings provide guidance for exploring single molecular devices with promising properties combined with graphene, fullerenes, and transition metals. [ABSTRACT FROM AUTHOR]