Pressure induced topological and topological crystalline insulators

Research on topological and topological crystalline insulators (TCIs) is one of the most intense and exciting topics due to its fascinating fundamental science and potential technological applications. Pressure (strain) is one potential pathway to induce the non-trivial topological phases in some topologically trivial (normal) insulating or semiconducting materials. In the last ten years, there have been substantial theoretical and experimental efforts from condensed-matter scientists to characterize and understand pressure-induced topological quantum phase transitions (TQPTs). In particular, a promising enhancement of the thermoelectric performance through pressure-induced TQPT has been recently realized; thus evidencing the importance of this subject in society. Since the pressure effect can be mimicked by chemical doping or substitution in many cases, these results have opened a new route to develop more efficient materials for harvesting green energy at ambient conditions. Therefore, a detailed understanding of the mechanism of pressure-induced TQPTs in various classes of materials with spin-orbit interaction is crucial to improve their properties for technological implementations. Hence, this review focuses on the emerging area of pressure-induced TQPTs to provide a comprehensive understanding of this subject from both theoretical and experimental points of view. In particular, it covers the Raman signatures of detecting the topological transitions (under pressure), some of the important pressure-induced topological and TCIs of the various classes of spin-orbit coupling materials, and provide future research directions in this interesting field.