Talk 22.05.2017

Speaker: Prof. Uwe Bovensiepen
University of Duisburg-Essen

Title: Probing electronic excitations in real time: What is it good for?

Abstract:
Thermodynamics provides excellent means to describe broken symmetry ground states of condensed matter in thermal equilibrium because the temperature determines the population of excited states and the resulting overall energy minimization leads to, e. g., structural transitions, magnetic order, or superconductivity. However, identification of the microscopic interactions, which generate such symmetry breaking, is far from trivial due to cooperation or competition of various interactions. Experiments in the time domain provide additional insights in this regard because they operate on the characteristic time scales of such interactions. In particular, femtosecond laser based pump-probe experiments address these time scales for elementary processes. Recent results from the fields of surface science [1], strongly correlated materials [2,3], and magnetism [4] will be discussed.
[1] Frigge et al., Nature 544, 207 (2017).