Jungiusstr. 11, Hörsaal AP
SFB 668 - Kolloquium
Prof. Oliver Waldmann (Universität Freiburg):
Molecular Nanomagnets: Toy Models for Mesoscopic Many-Body Quantum Physics
Molecular nanomagnets establish a new class of magnetic materials, which are not only aesthetically pleasing but provide a fascinating view on the quantum magnetism in small, mesoscopic objects. These molecules typically consist of tens of magnetic metal ions, which are linked by organic ligands such as to form well defined geometrical structures. They thus represent magnetic nanoclusters with ideal properties: they don't exhibit any form or shape dispersion and are virtually decoupled magnetically from each other. The magnetic exchange couplings between the metal ions within a molecule are frequently of antiferromagnetic nature, which gives rises to a competition between the quantum correlations injected by the antiferromagnetic paths and the constraints due to the topology of the lattice of metal ions. Spin frustration is a prominent example, but other complex many-body wave functions can emerge, yielding unprecedented magnetic behavior. In this talk the molecular nanomagnets will be regarded from the perspective of many-body physics in "small" quantum systems. Several examples of our work will be presented, which shall demonstrate the challenges in understanding the structure of the emerging many-body wave functions and their associate quantum magnetism in small spin systems.