CPM Seminar

Spin, orbital, and spin-orbit excitations in iridates

Young-June Kim

University of Toronto

An overview of electronic excitations in iridates measured with resonant inelastic x-ray scattering (RIXS) will be given. Unlike the first-row transition metal compounds, orbital angular momentum is not quenched for the Ir4+ ions in iridates. The spin-orbit coupling instead strongly couples spin and orbital moment, giving rise to an unusual spin-orbital entangled ground state. In particular, a square lattice iridates Sr₂IrO₄ and Ba₂IrO₄ exhibit physical and magnetic properties remarkably similar to those of cuprates, such as quasi-two-dimensional magnetism described by a large magnetic exchange coupling. We measured magnetic excitations in hole-doped iridates as a function of doping using RIXS. The observed magnetic excitation spectra will be compared with those of cuprates and possible routes to high temperature superconductivity will be discussed.