Imaging Sublattice Cooper-Pair Density Waves in Monolayer 1  T^{'}-MoTe_{2}

Unconventional superconductors that spontaneously break space-group symmetries of their underlying crystal lattice are distinguished by spatial modulations of superconducting order parameter. These states have recently captured significant attention in various strongly correlated materials, where the translational or intra-unit-cell symmetry breaking results in the emergence of pair density waves with wavelength extending across one or multiple unit cells. Here, we employ a spectroscopic-imaging scanning tunneling microscopy to reveal sublattice modulations of the superconducting gap magnitude, coherence strength, and subgap states in tunable 1 T^{'}-MoTe_{2} monolayer. These modulations are uniquely oriented perpendicular to the zigzag Mo chains at the scale of half a unit cell and coexist with three-unit-cell pair density wave modulations along the Mo chains, both of which attenuate with increasing temperature and external magnetic fields. Importantly, we find that the superconductivity modulations are strongly linked to unconventional electron pairing mechanisms, which significantly deviate from the Cooper pairing observed in conventional Bardeen-Cooper-Schrieffer superconductors. Our findings advance the knowledge of Cooper-pair density modulations and their intricate interplay with other symmetry-breaking states in strongly correlated superconductors.