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Abstract |
Topological materials have contributed significantly to technological advancements in the past few decades, and the discovery of three-dimensional (3D) Dirac semimetals (DSMs) has further expanded the field of topological semimetals. Based on whether they obey Lorentz invariance, 3D DSMs can be classified into type-I and type-II. Na3Bi and Cd3As2 have been confirmed as type-I, while PtTe2 is a representative material of type-II. These representative materials possess stable samples, mature preparation methods, and their theoretically predicted band structures have been experimentally verified, making them excellent platforms for extensive research. In this dissertation, we conduct theoretical research on their optoelectronic and transport properties using the random phase approximation (RPA) dielectric function and the energy-balance and momentum-balance equations derived from the Boltzmann equation. This thesis studies the nontrivial energy band structures of type-I 3D DSMs and the effects of topological properties on their optical conductivites and plasmons. Meanwhile, optical conductivites and lifetimes primarily governed by tilted Dirac cones of type-II 3D DSMs are also investigated. These investigations provide theoretical foundations for understanding the optoelectronic and transport properties of emerging topological materials and exploring their potential applications. |
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