Low Dimensional Carbon Based Nanostructure Fabricated With Benzene And Its Interaction With Magnetic Atoms

The Carbon based low dimensional materials have attracted broad interest due to their unique physical and chemical properties. There are examples like graphene, graphene nanoribbon, carbon nanotube, fullerene, organic chains and films showing great potential in practical application for next-generation transistors, optoelectronic devices and biological sensors. Besides their intrinsic properties, new properties and functions can be generated when combining with metal atoms. For example, some become superconducting when doped with alkali metal. Some acting as assembling template or endohedral matrix for transition atoms can work as spintronic devices and single molecular magnet respectively, and these systems may also show Kondo effect which is very important for studying electron strong corelation. In this thesis, we investigated a new unreported low dimensional carbon based nanostructure using low temperature scanning tunneling microscope (STM). The nanostructure was fabricated with benzene on Cu(111) using chemical vapor deposition method in ultrahigh vacuum. We also investigated the interactions between the nanostructure and cobalt atoms.In the first chapter, we introduced the history, theory and hardware of STM and the STM we used in our experiments. We also introduced the density functional (DFT) method and the method of simulating STM image.In the second chapter, we firstly introduced some common low dimensional carbon based materials, then illustrated the method of fabricating our new nanostructure and results of STM, XPS characterization, DFT simulation. We found that the nanostructure has c(2×7) reconstruction on Cu(111) and a semiconductor character with band gap of0.8eV. Combining with XPS results, we speculate that the nanostructure has conjugated π electron states with edges and copper adatoms are also involved into it. According to these experimental information, we suggested a possible polyphenylene model and simulate STM image and tunneling spectra with DFT method, the simulated results fit well with experiments.In the third chapter, we firstly introduced magnetic anisotropy and Kondo effect and then illustrated the results of depositing cobalt atoms on the nanostructure. We found that even at ambient temperature, cobalt atoms can disperse on the nanostructure without aggregating into cobalt islands. After it was annealed under400K for30min, the cobalt atoms diffused to specific sites to form local ordered chains. DI/dV tunneling spectra on cobalt atoms show Kondo resonance which indicates the preserved atomic magnetism of cobalt. We also investigate potassium’s adsorption on the nanostructure simply.