Study On Electrical Transport Properties Of Zero And One-Dimensional Multi-Membered-Ring Carbon-Based Nanostructures

With the popularity of electronic products,people put forward higher requirements for the performance of electronic components.Manufacturing low power consumption,small size,low cost,high quality electronic devices is the development direction of information industry.As one of the emerging technologies,nanotechnology provides the technical basis for the continuous innovation of new materials and devices.Since 1985,the successful preparation of fullerenes,graphene and other nanomaterials has triggered an upsurge of research on low-dimensional carbon-based nanomaterials.Among them,zero and one-dimensional carbon-based nanostructures have attracted rapid attention due to their distinct characteristics from two-dimensional nanostructures.Based on this,the transport properties and internal mechanism of several zero and one-dimensional multi-membered-ring carbon-based nanostructures are studied by means of density functional theory and non-equilibrium Green’s function.Firstly,based on the successful synthesis of Heptauthrene molecules experimentally,the authors study the spin transport properties of Heptauthrene molecules coupled with gold electrodes through different contact sites,and find that the spin polarization of the system can reach any value in the range of [-100%,100%] by adjusting the gate voltage.Further analysis shows that the regulation of spin polarization is closely related to the bidirectional movement of transmission peaks near Fermi level.Secondly,according to the first principles,the authors study the electronic properties of trapezoidal graphene nanoribbon,and find that the band gap of nanoribbons with different widths and boron and nitrogen doping shows a certain regularity.In addition,electron transport properties of trapezoidal graphene nanoribbon containing metallic elements(copper,iron,aluminum)are also investigated,and the spin Seebeck effect is found to be an inherent characteristic of the system.Finally,in this paper,the three-terminal device is constructed with tetrathiafulvalene tetrathiolate.It is found that the transport properties of the device can be effectively regulated by changing the end atoms of the molecule connected with the gold electrode.Different from the traditional ferromagnetic method,this paper uses electrical method to trigger the spin flip and realizes the precise control of the spin polarization of the system,which will provide a new idea for the preparation of electronically controlled spin filters.In addition,spin polarization modulation is robust to the selection of end atoms of the molecule,which will be very beneficial to the fabrication of practical devices.