transport phenomena in topological semimetals.pdf

The discovery of topological materials insulators has increased the research activity in this domain. Weyl/Dirac Semimetals which are 3D phases of matter with gapless electronic excitations, the Dirac equation predicted the existence of antimatter and reconciliates special relativity and quantum physics by using a 4-dimensions vectors representing the wave function, this equation is the key to describe the topological phenomena and some anomalies in quantum fields theories. Weyl used a simple formulation of Dirac equation by utilizing Pauli matrices, this simplification leads us to the concept of Weyl fermions (massless fermions). Until now no Weyl fermion candidate have been discovered in LHC. This particle coupled with magnetic field leads us to some unphysical results like the non-conservation of electrical charge (chiral anomaly). There is also a major consequence of Weyl nodes which is the impact of berry curvature (it cannot be observed without breaking time reversal or inversion symmetry which produces the signature of Weyl semimetals called Fermi arcs) that can induce planar hall effect.