Engineering Layered Topological Semimetals: Novel States and Phase Transitions

Materials with exotic properties have become a key driver in advancing condensed matter and materials physics. Layered materials, in particular, offer exceptional platforms for exploring a wide range of quantum phases and phenomena. The distinct structural characteristics of these compounds allow for significant tunability through chemical or mechanical methods, enabling precise manipulation of electronic states and properties. Moreover, the ability to obtain atomically thin flakes of these materials opens up new possibilities for studying novel properties in reduced dimensions and for creating intricate material designs by constructing various heterostructures.

This talk provides an overview of our recent work on engineering ZrSiS-type layered topological materials to achieve new phase and properties. These materials exhibit multiple topological Dirac states stabilized by distinct symmetries, establishing them as a versatile platform for exploring novel quantum phenomena. In the non-magnetic compounds within this family, quantum oscillations reveal novel surface states emerging through symmetry reduction. In the magnetic versions, particularly the LnPS model system where magnetism is introduced by magnetic lanthanides (Ln), we observed a magnetic field-driven insulator-to-metal transition, accompanied by an exceptionally large and isotropic magnetoresistance - a rare and intriguing phenomenon.