UC Riverside

The merger of topology and symmetry established a new foundation for understanding the physics of condensed matter, beginning with the notion of topological insulators (TIs) for electronic systems. The "helical" mode at the system boundary, which is the ID edge of a 2D topological insulator or the 2D surface of a 3D topological insulator, is crucial for time-reversal invariant TIs. The complete lifting of spin-degeneracy while maintaining time-reversal symmetry makes these helical modes the ultimate limit of spin-orbit coupling. For proposals to realize unusual excitations like the Majorana bound state, this characteristic is essential. In this dissertation, I present a series of experiments investigating electronic transport of monolayer WTe2. By bringing monolayer 1T’ WTe2, a two-dimensional quantum spin Hall insulator, and few-layer Cr2Ge2Te6, an insulating ferromagnet, into close proximity in an heterostructure, we introduce an interfacial exchange interaction to transform the former into a ferromagnetic quantum spin Hall insulator, manifested by the anomalous Nernst effect, anomalous Hall effect as well as anisotropic magnetoresistance effect.