Electronic and Magnetic Properties of the Cuprates, Iridates, Rutheno-Iridates:

Thesis advisor: Michael J. NaughtonSynchrotron based experiments of quantum coupled states reveal a delicate balance of energy levels facilitating the Mott driven antiferromagnetic state responsible for High Temperature Superconductivity (HTSC). High resolution spectroscopic experiments including Angle Resolved Photoemission (ARPES), Resonant Elastic X-ray Scattering (REXS), X-ray Natural and Magnetic Circular Dichroism (XNCD & XMCD) are used to investigate the Cuprate, Iridate, and Rutheno-Iridate systems. Highly correlated Mott driven systems producing the antiferromagnetic Cuprate and Iridate series of layered perovskites are perturbed using doping and temperature to elucidate the correlation of states within the materials. Similar to the Cuprate HTSC, the Rutheno-Iridate system undergoes a phase segregation of magnetic domains resulting in Sr₃IrRuO₇ where ARPES measurements reveal a temperature and momentum dependent pseudogap. Electronic band structure investigations yield a Fermi surface with gap parameters similar to extended s-wave symmetry. Additional observations of a p-wave symmetry centered at the (π, π) scattering vector within Fermi surface maps provide evidence for long range magnetic coupling.Thesis (PhD) — Boston College, 2019.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Physics