Spin Currents in Unconventional Systems
16th October 2017, PHYSIKALISCHES KOLLOQUIUM, Ruhr-Universität Bochum H-NB
Start: 16th October 2017 12:00
End: 16th October 2017 01:00 p.m.
Martin Gradhand, University of Bristol UK
Ilya Eremin, Ruhr-Universität Bochum
Spin-orbit driven effects, have been under intensive research over the past decade. The growing interest in this area is partially driven by its technological significance in the area of magnetic random access memory (MRAM). In the wake of this technological interest, rather traditional effects such as the anomalous Hall effect came back into focus since it shares similar driving mechanisms but is much easier accessible experimentally.
In this talk I will introduce the basic concepts for spin - orbit driven transport phenomena involving th e Berry curvature of Bloch electrons which is intimately related to topological invariants characterising Chern and toplogical insulators. Furthermore, I will discuss the effect of targeted impurity doping on various transport properties. In order to put t his work into context I give a brief introduction to the technological aspects of the ongoing research on MRAM devices.
Finally, I will put the specific effects into a broader framework of linear response theory, where the existence of transport phenomena is intertwined with the symmetry of the underlying system. This allows us to exploit charge and spin Hall effects to probe novel states of matter such as chiral charge density wave phases as well as unconventional superconductivity with the extension of the Berry curvatures to the superconducting state.