Institute of Solid State Physics

SS22 WS22 SS23 WS23 SS24 WS24      Guidelines for Master Students

Strong Correlations and Spin-Orbit Coupling in (Double) Perovskite Oxides
Markus Aichorn
Institute for Theoretical and Computational Physics, TU Graz
https://tugraz.webex.com/tugraz/j.php?MTID=mb4a9f2f408c4f62d047f9f781fac0630
11:15 - 12:15 Wednesday 25 May 2022 PH01150

Strong electron correlations appear when the kinetic energy in a system is comparable or smaller than the repulsive Coulomb interaction energies. Until a few years ago his behavior was attribute in transition metal compounds almost exclusively to materials with open 3d shells, and just a few studies on a limited amount of systems have been done outside of this play ground. Only in the last decade, it has been noted that also systems with 4d or even 5d electronic states in the conduction bands can show very interesting and unexpected behavior, such as spin-orbit assisted insulators.

Motivated by these interesting materials, we investigate the interplay of spin-orbit coupling and electronic correlations. Using a simplified model, we can obtain general trends as function of system parameters. Importantly, the importance of spin-orbit coupling depends strongly on the band filling, since it is related spin-orbit polarisation effects.

We will also relate the model findings to real materials. We highlight the difference between 4d and 5d transition metal oxides. We also look at the insulating states of double-perovskite osmates and iridates, and discuss their magnetic ground states.