Seminar

Abstract

Competing interactions of spin with charge and lattice, determined by the spin-orbit interaction,
give rise to rich phase diagrams of states in novel correlated electron materials. In such
materials, magnetically ordered phases are very often in direct competition with other ordered
phases, such as a spin- or charge-ordered phase. Unfortunately, the dominant interaction
responsible for the formation of a particular phase is often difficult to determine at thermal
equilibrium, so that a fundamental understanding of the underlying competing interactions is
out of reach using static measurements. Time-resolved spectroscopy techniques have the
potential to overcome these limitations by temporally driving the material system out of
equilibrium. The subsequent relaxation pathways are then determined by the spin-charge lattice
interactions, which can be studied using different photoemission techniques.

In this talk I will show how recent developments in ultrafast light sources and photoemission
detector technology have paved the way for a completely new generation of time- and spin-
resolved photoemission experiments. With this tool at hand we can directly observe the
temporal evolution of excited carriers and spins in energy, momentum space and time,
providing an unprecedented insight into the fundamental energy and (angular) momentum
dissipation mechanisms even in complex condensed matter systems. I will focus in particular
on two-dimensional van der Waals materials and molecular-based heterostructures.