Paramagnons in the extremely overoped cuprate La2-xCaxCuO4

The high-Tc cuprate superconductors feature a complex phase diagram involving various ordering phenomena besides superconductivity, such as charge and spin density waves. It has been widely suggested that antiferromagnetic (AFM) fluctuations, surviving upon doping the AFM Mott insulator parent compounds, play a key role in the cooper pairing mechanism and the formation of charge density waves in these materials. Our group recently succeeded in growing high quality thin films of La2-xCaxCuO4 (LCCO) in the overdoped regime with dopings up to x = 0.5 and observed that superconductivity as well as charge ordering surprisingly persists up to at least x = 0.5. Here, we propose to carry out Cu-L3 resonant inelastic x-ray scattering (RIXS) on LCCO thin films to systematically investigate the evolution of dispersive magnetic excitations in the overdoped regime. The aim is to understand the extent to which AFM fluctuations determine the superconducting and charge density wave phase boundaries.