Structural modulated inteplay between charge and spin in the pseudospin-1/2 state within Slater-Mott crossover regime

Systems described by the Hubbard Hamiltonian sitting on bipartite lattices are important for capturing the correlated physics of various emergent phenomena, including high temperature superconductivity in the cuprates. The emergence of pseudospin-1/2 state on a square lattice in the layered perovskite iridate has provided an alternative system akin to the parent compound of cuprates with a similar antiferromagnetic Mott insulating state. Moreover, the much stronger spin-orbit coupling and relatively weaker electron correlation of the pseudospin-1/2 electrons have resulted in novel electronic and magnetic behaviors that are absent or could not be captured in the cuprate family. This includes the strong collective spin-charge fluctuations in an intermediate regime of the Hubbard Hamiltonian, which is also referred as Slater-Mott crossover regime. In virtue of epitaxial strain tuning of iridate thin films, we show that the pseudospin-1/2 electronic state is highly susceptible to structural degree of freedom, enabling an effective tuning of the electron correlation within the crossover regime. Our combined results on transport properties and synchrotron-based x-ray scattering reveal the electronic and magnetic responses to the correlation modulation in both the 2D and 3D regimes.