Promoting Unconventional p-wave Superconductivity in Transition Metal Dichalcogenides

The hole-doped monolayer transition metal dichalcogenides have a pronounced spin-valley locking feature in which the low-energy physics is characterized by spin-oppositely-polarized Fermi pockets at opposite valleys separated in momentum space. This unique structure offers new possibilities for broken symmetry phases. Due to the d-character of the electrons, strong correlation effect allows the realization of a p-wave superconducting state consisting of two intra-pocket paired chiral p-wave condensates. In addition, each intra-pocket pairing order parameter has a spatially-modulated phase, akin to the FFLO states, associated with spontaneous supercurrent loops on the unit cell scale. Under time-reversal symmetry, the chiralities of the two condensates are opposite and the counter-propagating current loops of the two condensates cancel each other. We show that circularly-polarized photoexcitation exhibits chirality-dependent pair-breaking effect on the chiral p-wave states. This chirality-selective circular dichroism provides an experimental approach to promote one chiral condensate than the other. We then investigate the interesting properties of the superconducting state dominated by one FFLO-type topological condensate.