Spin-orbit coupling and correlations in iridates
February, 20th 2013 - 11:00 am
Seminar by Dr.ssa Maria Daghofer
IFW, Institute for Theoretical Solid State Physics, Dresden (Germany)
Title: Spin-orbit coupling and correlations in iridates
Location: Room 15, - 4th floor, buiding 9, Dipartimento di Fisica - Università di Salerno
Abstract
In recent years, spin-orbit coupling has generally attracted large interest due to its importance in topological insulators. Substantial attention is currently also paid to iridates, as they combine strong spin-orbit coupling with substantial correlations, which raises expectation of novel phases like ``topological Mott insulators''.
The $5d$-$t_{2g}$ levels of iridium contain one hole, at large Coulomb repulsion, low-energy features can be described by a superexchange model, but due to the strong spin-orbit coupling the relevant quantity is not a spin, but a doublet with total angular momentum $j=1/2$. Compared to a spin, this pseudospin tands to have more anisotropy that determine differences between single- and bi-layer square-lattice iridates. I am also going to discuss a for spin-orbit-coupled and correlated electrons on a triangular lattice, where frustration induces exotic phases like a $\mathbb{Z}_2$-vortex lattice.