Electronic properties in graphene-related systems

Abstract

In this dissertation we use first principle calculations to study the geometric and electronic properties in group IV graphene-related systems ranging from one-dimension edge-decorated graphene nanoribbons to two-dimensional graphene ripples with different corrugated directions periods and curvatures Various decorating atoms different curvature angles and the zigzag edge structure have resulted in three types of geometric structures depending on the edge-edge interactions The existence of low-lying peaks of densities of states can be used to distinguish specific types of graphene ripples obtained in STS experiments As a counterpart of graphene hydrogenated silicenes with different hydrogen configurations and concentrations lead to tunable band gaps and strong localized states at the Fermi level providing a method to identify the hydrogen concentrations A self-developed generalized tight-binding model is used to study the electronic thermal properties of the nanostructures from two-dimensional graphene to three-dimensional graphites with different stacking configurations The temperature and the magnetic field compete with each to determine the specific heat of graphene revealing a simple linear relation between critical temperature and critical magnetic field In bulk systems the interlayer atomic interactions dominate the temperature-dependent specific heat exhibiting linear T dependences in low- middle- and high-temperature for Bernal rhombohedral and simple hexagonal graphites respectively We have paid attention to compare the calculations with the experiments and have obtained some novel features not yet verified experimentally

Date of Award	2015 Mar 30
Original language	English
Supervisor	Min-Fa Lin (Supervisor)