First-principles Study Of Two Novel Fullerene Molecules

In the recent decades, fullerenes have attracted wide research interest because of their novel structures and potential applications. To determine the geometric and electronic properties of the novel fullerenes, various experimental measurements as well as theoretical calculations and simulations are required. Here, we focus on TiY₂N@C₈₀ and C₂₈ molecules based on our density functional theory calculations. In this thesis for Master Degree includes the following three chapters.In chapter 1, we give a brief description on density functional theory (DFT), and the nonequilibrium Green's function technique combined with DFT. In the end, a short introduction for software packages used in this thesis is presentedIn chapter 2, after briefly introducing the fullerenes and endohedral fullerenes, we present a DFT study on a novel metallofullerene, TiY₂N@C₈₀. Through optimizing the geometries, simulating its IR spectra, and calculating density of states and spin density, we determine the stablest configuration of TiY₂N@C₈₀ molecule and the chemical valence states of the encaged metal atoms in C80, and assigning the vibration peaks of the experimental measured IR spectrum. Then we try to manipulate the electronic properties of TiY₂N@C₈₀ molecule. The calculated results indicate that the magnetism of TiY₂N@C₈₀ molecule could be quenched by carrier doping, while the height of rotation barrier is obvious enhanced by functionalized C80 cage.In chapter 3, we focus on the adsorption and transport properties of C₂₈ molecule on Au(111) surface. Theoretical predictions show that the magnetic moment of C₂₈ molecule significantly reduced due to the molecule-substrate interaction. C₂₈ molecule can be used to design a efficient spin-filter.