Experimental investigation of topological superconductors

Topological quantum materials have sparked great interest to pursue electronically nontrivial phases. It is expected this new trend will keep on producing more exotic discoveries about novel quantum phases of topological matter. Regarding topological superconductors the physics of dispersive Majorana fermions on the surface is a new field of research, and also it is important for future applications in quantum computation. Investigating new types of topological phenomena in real materials is significant for both developing new devices and verifying theoretical models and predictions. Intrinsic topological superconductors are rare in nature, several concrete cases have been investigated extensively, such as Sr₂RuO₄, Cu_xBi₂Se₃, Sn₁-_xIn_xTe and several noncentrosymmetric superconductors. The presence of Weyl and Dirac semimetals as a 3D analog of graphene shed further light on topological superconductors with their characteristic electronic properties, for instance protected Fermi surface states and a novel response to applied electric and magnetic fields. In this thesis we presented the experimental results on the type II Dirac semimetal PdTe₂ (Chapter 4-6) and the topological superconductor candidate Sr_xBi₂Se₃ (Chapter 7). Magnetic and transport measurements, and muon spin relaxation experiments were carried out to unveil the superconducting nature as well as its interaction with topological features.