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Abstract:
In the present thesis, the electronic properties of three types of quasiparticles are investigated in topological non-trivial materials: Weyl fermions, triple point fermions and Dirac fermions. Theoretical calculations of electronic band structures for these systems are performed by means of ab-initio methods and in the framework of Density functional theory. The related topological invariants are calculated based on Berry curvature concept within the basis of maximum localized Wannier functions. The electronic transport properties of the Weyl metals, such as the intrinsic anomalous Hall effect (AHE) and spin Hall effect, are analyzed and calculated using Kubo formula. To investigate the surface states originating from these quasiparticles, both a half-infinite surface model and a slab model are utilized and give consistent results. The prior model is performed using a Green's function technique and the latter via the ab-initio methods. Some of our predictions have been observed experimentally, such as the AHE in Mn3Ge and the quantum oscillations in PtSe2, while others still require experimental verification.
