The Role of Charge Doping in High Entropy Perovskite Oxides

Disorder is an important aspect of correlated quantum systems. As examples, it can be used to manipulate superconductivity, magnetic ordering, and enable scaling of non-fermi liquid responses. While synthesis of new quantum materials is generally focused on creating perfect crystals comprised of only a few elemental building blocks, we will present our recent efforts to create high quality single crystals with a high degree of configurational elemental disorder on sublattice sites. Complex crystal structures comprising two or more sublattices, such as those in the perovskite family, are particularly promising. This is due to the nearest neighbor cations on one configurationally disordered sublattice being tied together by an intermediate common and uniform anion sublattice. We will present our recent stabilization of single crystal epitaxial films of the ABO₃ perovskite, La(Cr_0.2Mn_0.2Fe_0.2Co_0.2Ni_0.2)O₃. Hole doping the A site with Sr is shown to give access to unexpected functional responses, as demonstrated by transport, magnetometry, x-ray spectroscopy, and neutron studies.