Pairing symmetry of SrRuO₃-SrTiO₃ ruthenate superlattice

The unconventional superconductivity of Sr₂RuO₄ has been studied extensively due to the claim of unique p-wave pairing state, which is under recent scrutiny. One of the main difficulties of determining the pairing symmetry is the accurate estimation of relevant energy scales, which are competing. Small tuning of the microscopic parameters and the resulting evolution of pairing symmetry can offer more insight in the field, which is not easy from the experimental side due to the requirement of extremely clean sample and high-precision measurement. Here, based on the recent proposal of possible superconductivity in SrRuO₃-SrTiO₃ superlattice, we investigate the pairing symmetry of the system, which can be comparable target of Sr₂RuO₄. From a DFT calculation, we construct a tight-binding Hamiltonian and search for the pairing symmetry of the heterostructure by calculating the superconducting phase transition temperature. We also study the possibility of pairing transition by tuning the external parameters, which is attainable through epitaxial strain.