MoTe2: Semiconductor or Semimetal?

Transition metal tellurides (TMTs) have attracted intense interest due to their intriguing physical properties arising from their diverse phase topologies. To date, a wide range of physical properties have been discovered for TMTs, including that they can act as topological insulators, semiconductors, Weyl semimetals, and superconductors. Among the TMT families, MoTe 2 is a representative material because of its Janus nature and rich phases. In this Perspective, we first introduce phase structures in monolayer and bulk MoTe 2 and then summarize MoTe 2 synthesis strategies. We highlight recent advances of Janus MoTe 2 in terms of material structures and emerging quantum states. We also provide insight into the opportunities and challenges faced by MoTe 2 -associated device design and applications.