Unidirectional charge and pair density waves in topological monolayer 1T′−MoTe2

Symmetry-breaking phenomena are identifiable in numerous strongly correlated systems including high-temperature superconductors. However, identification of these exotic states and understanding their interplay with superconductivity in topological materials remains limited. Here we employ cryogenic scanning tunneling microscopy to reveal coexistent charge and pair density waves (CDWs and PDWs) in topological monolayer 1T^'-MoTe₂. The two orders are modulated unidirectionally and share the same periodicity of five unit cells or a wave vector near (0, 0.4)π/b (b is the lattice constant along the zigzag Mo chains). Importantly, the PDW features a two-gap superconductivity below a transition temperature of around 6.0 K and induces a unique secondary particle-hole-symmetric CDW at twice its wave vector. Combining these results and our density functional calculations, we elucidate that the two unidirectional orders are driven by nesting behaviors between electron and hole pockets. Our findings establish monolayer 1T^'-MoTe₂ as a topological paradigm to explore multiple preexisting symmetry-breaking states.