Study On Electrical Transport Properties Of Low-dimensional Carbon And Chalcogenide Nanostructures

With the continuous progress of science and technology,people put forward higher requirements for devices,and the research of nanomaterials is more in-depth.Low dimensional carbon chalcogenide nanostructures exhibit excellent electrical properties due to their special structure,such as current switching,rectification effect,negative differential resistance effect,etc.Based on this,the authors use density functional theory combined with non-equilibrium Green’s function to study the electron transport properties of carbon-based chain benzene molecule,corrugated transition metal chalcogenides nanoribbons and 3,4,9,10-perylene tetracarbodic anhydride molecules,find interesting electron transport properties such as differential resistance effect,spin polarization phenomenon and spin Sebeck effect,and elucidate the physical mechanism of transport properties.Firstly,based on the successful synthesis of benzophene polymers in experiments,the authors design different sizes of carbon chain benzophene molecules and calculate their electron transport properties.It is found that the negative differential resistance effect exists in all the carbon chain benzobenzene molecules,although the length of the molecules varies and the size of the benzene monomers that make up the molecules varies.After the analysis,it is found that negative differential resistance effect is the essential characteristic of carbon chain benzophenes.Secondly,the authors study the electron transport properties of corrugated transition metal chalcogenides（Mo S₂,Fe Se₂,Ni Te₂）nanoribbons with different edge configurations,bending shapes,and bending degrees.It is found that the transition metal chalcogenides nanoribbons with different edge configurations have two different properties:metallic and semiconductor.In addition,the bending degree of transition metal chalcogenide nanoribbons can lead to the change of spin polarization and metal-semiconductor transition.Finally,the authors study the electron transport properties of 3,4,9,10-perylene tetracarboxylic dianhydride molecules coupled with different metal electrodes.It is found that the system presents spin Seebeck effect,and is not affected by electrode metal elements,and has strong robustness.In addition,by applying gate pressure to the device,it is found that the spin polarizability can be precisely regulated by electrical means,which will be beneficial to the development of spintronic devices.