Two-Fold Anisotropic Superconductivity in Bilayer T_d-MoTe₂

Non-centrosymmetric 2D superconductors offer an opportunity to explore superconducting behaviors with strong spin-orbit coupling. Among the non-centrosymmetric families, T_d-MoTe₂ is a representative material because of its rich phases. Notably, T_d-MoTe₂ is the first 2D materials that demonstrated a coupling between ferroelectricity and superconductivity, and this ferroelctric switching can be simply controlled by electrical gating. Here, we will present on the superconducting behavior in bilayer T_d-MoTe₂ under an applied magentic field along different directions in-plane, and under different displacement fields and doping densities. We find that bilayer T_d-MoTe₂ has a two-fold symmetric superconducting behavior as a function of in-plane magnetic field angle that maximizes along the a-axis, parallel to the mirror plane. Importantly, large violations of Pauli limiting are observed, and DFT calculation suggests the anisotropic superconductivity in bilayer MoTe₂ is likely driven by Ising-like spin-orbit coupling. In addition, the two-fold anisotropy is preserved in the entire superconducting region, even with the interaction of strong Rashba spin-orbit coupling, and we find that the two-fold symmetric superconductivity remains after the ferroelectric switching. Our findings generally agree with previously observed results in multilayer and monolayer T_d-MoTe₂ and the expected spin-orbit enhanced upper critical fields as found in DFT calculations.