Tunable Superconductivity in Bilayer T_d-MoTe₂

Van der Waals heterostructures of encapsulated, low-carrier density superconductors offer a unique platform to study 2D superconductivity in the clean limit. Furthermore, their properties can be tuned with an electrostatic gate, enabling the observation of phase transitions. In this talk, we will present recent results on superconductivity in bilayer T_d – MoTe₂. Bilayer T_d – MoTe₂ features small electron and hole pockets of nearly equal size. We show that superconductivity in this system is maximized when the hole and electron densities are equal. Eliminating either one via electrostatic gating renders the material ‘normal’, giving us a dome-shaped superconducting phase diagram vis-a-vis doping and temperature. These results show that the likely scenario is one where superconductivity is mediated by interband pairing between the electron and hole pockets. We confirm this scenario with DFT and tight-binding calculations of the electronic structure and charge susceptibility, which shows strong nesting near charge compensation.