Electronic structure of Ruddlesden-Popper nickelates under strain

Signatures of superconductivity under pressure have been recently reported in bilayer and trilayer Ruddlesden Popper (RP) nickelates with general chemical formula R_n+1Ni_nO_3n+1 (n= number of perovskite layers along c and R= rare-earth). The emergence of superconductivity is always concurrent with a structural transition in which the octahedral tilts are removed and the out-of-plane d_{z^2} orbital overlap increases. Here, we explore strain (compressive and tensile) as a means to mimic the electronic structure characteristics of RP nickelates (up to n=6) under hydrostatic pressure. Our findings highlight that strain allows to decouple the structural and electronic structure effects obtained by applying pressure to this material and can be a promising alternative route to achieve superconductivity.