Microstructure, Magnetic and Electronic Ordering: Interplay and Interactions

784. WE-Heraeus-Seminar

16 Apr - 19 Apr 2023


Physikzentrum Bad Honnef

Scientific organizers:

Prof. Dr. Gabi Schierning, U Bielefeld • Prof. Dr. Andreas Hütten, U Bielefeld • Prof. Dr. Kai Rossnagel, U zu Kiel

Charge density wave (CDW) phases, also known as Peierls instability, form by non-diffusive structural phase transitions along 1D monoatomic chains, but also in 2D materials. The CDW phase results in a new band structure, comparable to that of a semiconductor, as well as a charge density modulated in real space - i.e. a charge order - which follows this characteristic length. In electrical transport, this results in strongly non-linear I-V characteristics. Incommensurate periodic lattice distortion, the softening of certain phonon modes and Fermi-surface nesting accompanies this phase transition. How does this look in 3D? The most famous example of a non-diffusive structural phase transition in 3D is certainly the martensitic phase transition. Experimental data as well as theoretical work point to similar electronic ordering phenomena in those 3D non-diffusive structural phase transitions. This forms the link to magnetic ordering. The magnetocaloric materials of the first order are characterized by the combination of the magnetic phase transition with the simultaneous change in the lattice structure. The general physical focus is on the analysis of all entropy contributions, e.g. from the lattice transition, the change in magnetization and the contribution of the electrons, in order to understand these results with the underlying microstructural picture of this correlated phase transition. Such investigations can be carried out experimentally in situ in high-resolution state-of-the- art microscopy, providing the input for theory. In this seminar, the fundamental aspects of microstructure, magnetic and electronic ordering: interplay and interactions with regard to phase transitions on the atomic, nano- and microscopic scale are discussed.

The seminar is dedicated to a specialized public and is restricted to 80 participants among which there are around 15 invited speakers and several contributed speakers, as well as poster presentations. Emphasis is set on giving young investigators at the PhD or PostDoc level the opportunity to participate.

The conference language will be English. The Wilhelm and Else Heraeus-Foundation bears the cost of full-board accommodation for all participants.