Lifshitz Transitions Induced by Temperature and Surface Doping in Type-II Weyl Semimetal Candidate T_d-WTe₂

Using high resolution angle-resolved photoemission spectroscopy, we systematically investigate the electronic structure of T_d-WTe₂, which has attracted substantial research attention due to its diverse and fascinating properties, especially the predicted type-II topological Weyl semimetal (TWS) phase. The observed significant lattice contraction and the fact that our ARPES measurements are well reproduced by our ab initio calculations under reduced lattice constants support the theoretical prediction of a type-II TWS phase in T_d-WTe₂ at temperatures below 10 K. We also investigate the evolution of the electronic structure of T_d-WTe₂ and realize two-stage Lifshitz transitions induced by temperature regulation and surface modification, respectively. Our results not only shed light on the understanding of the electronic structure of T_d-WTe₂, but also provide a promising method to manipulate the electronic structures and physical properties of the type-II TWS T_d-XTe₂.