| Summary: | 碩士 === 國立成功大學 === 物理學系 === 103 === We use the generalized tight-binding model to study fundamental electronic properties of twisted bilayer graphene. The main consideration is on a system which has mutual enlarged cell. The carbon atoms on the same layer only include the π bond in 2pz orbital. On the other hand, there exist the complex π and σ bonds between the different layers. These interactions lead to the extensive electronic properties. The energy band structure presents the asymmetric linear, parabolic energy bands with isotropic and non-isotropic coexistence. The valence and conduction bands overlap each other to form a semi-metal. The critical characteristics of the energy bands are determined by the twist angle which is directly reflected into the density of states (DOS). The DOS spectrum presents shoulder structure and symmetrical divergence peaks. They are, respectively, related to the extreme points and saddle points.
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