Theoretical Studies on Transport and Photoresponse Properties of a Wheel-and-Axle Architecture Formed by Nitrogen-Doped Graphynes and a V_m(Bz)_n Nanowire

Theoretical studies are carried out on a “wheel-and-axle” architecture, (NDGY)_k-V_m(Bz)_n, by using density functional theory, nonequilibrium Green’s function (NEGF), and Keldysh nonequilibrium Green’s function (KNEGF) methods. Here, (NDGY)_k and V_m(Bz)_n denote the wheels formed by nitrogen-doped graphynes and the axle formed by a one-dimensional (1D) vanadium benzene nanowire, respectively. The electronic structure, transport property, and linear photoresponse of (NDGY)_k-V_m(Bz)_n are investigated. Within the range of 0.0 ~ 1.0 V except at 0.5 V and 0.6 V bias voltages, (NDGY)_k-V_m(Bz)_n shows a spin polarized transport character as the minority spin state serving as the primary transport path. The spin filter efficiency (SFE) of (NDGY)_k-V_m(Bz)_n can reach 100%, suggesting a good candidate for spin filter. Interestingly, a nonpolarized transport character is found at 0.5 V and 0.6 V bias voltages owing to the opening of the majority spin channel and leading to a negative differential resistance behavior entailing it for making electronic oscillators, electronic switches, and spin switches. When applied light irradiation, the minority spin state gives rise to stronger photoresponse than the majority spin state. Moreover, the magnitude of photoresponse can be tuned by the photon energy. All of these fascinating properties of (NDGY)_k-V_m(Bz)_n give a clue toward exploring new wheel-and-axle architectures with potential applications in electronic and optoelectronic devices.