The Research Network
is funded by the
Also in the last funding period, the investigation of the optical and magnetic properties of nanostructures constituted a research area. This allocation makes sense as the research field has undergone a rapid evolution especially with focus on its fundamental and applied aspects. Nevertheless, the optical and magnetic properties are intimately linked to the electronic degrees of freedom of matter and thus research area D is closely related to area C. Taking into account that in most projects complex ordered assemblies of nanostructures and not individual nanoparticles or -wires are investigated, aspects of self-organization and bottom up patterning approaches strongly enter the area linking it to area B. Characteristic for all projects in D is that complementary competences need to be combined to successfully tackle the research tasks. This is reflected in the newly formed teams combining expertise from the different involved research institutions. Only due to the wide know-how available within the network, the projects are feasible illustrating the immense benefits of the multi-institutional collaborations in the network.
There are two individual projects on nano-optics and nano-photonics in research area D, one on the anticipated non-linear optic effects in nanostructures and one on optical nano-bio-analytics. Project D2 focuses on plasmonic effects. Light will be coupled in resonantly to metallic nano-antennas, traveling as surface plasmons and focused to a nano-junction, in which strongly enhanced electrical fields are generated that interact with molecules or nano-particles to achieve optical non-linearities. Thus, the supported nano-antennas focus the electrical field on e.g. lithiumniobat particles to cause higher order effects. Single antennas and arrays of antennas will be investigated. In this project the complementary know-how on photon detection and simulation of optical fields from Stuttgart is combined with the expertise from Freiburg on crystalline lithiumniobate nano-particles. Similarly, in project D8 metallic nanostructures are used to enhance the optical signal in the mid infrared region (3-15 μm) and to perform chemical analysis on the nanoscale with a newly designed sensor.
Four projects within area D deal with the magnetic properties of nanostructures, i.e. with research related to spintronics. Project D3 investigates the interaction of molecular magnets with the conduction electrons of graphen, onto which the molecules are adsorbed, in order to realize hybrid graphen-molecule spin valves. Central to project D5 and D7 is the local control of spin on two complementary systems and with different technical approaches. In project D5, dopant-vacancy complexes in diamond will be created and individually integrated in p-i-n structures, in which the p-doped part will be made from focused ion beam (FIB) patterned nano columns. The initial studies on radiative recombination in such structures promise interesting results on the quantum-optical properties of single photon emitters. The main aspect of this work will, however, be the electrical detection of spin-related phenomena in the I-V curves of the devices. In contrast, project D7 aims at detecting and manipulating the spin of individual magnetic molecules on surfaces using scanning tunneling microscopy (STM). The molecules should be switched between two different magnetic states (high spin and low spin) by the local tunneling currents or photons. Finally, project D6 deals with the magnetic properties of thin magnetic films that are patterned with nano-sized holes (anti-dots). As prior studies have shown, the structures can be vastly tuned from the limit of nm-wide and connected metal wires to quasi continuous films with a low surface fraction of antidots. Such percolated patters are discussed as future data storage media and thus, their magnetic properties and magnetization dynamics are of high interest. As a consequence, the focus of project D6 lies on synchrotron-based techniques to measure the time resolved magnetization dynamics of the differently percolated structures.
The synergies of the competences of the different partners combined in individual teams and projects are essential for these interdisciplinary projects. In research area D, theoretical and experimental physicist, chemists from organic and inorganic synthesis and chemical analysis as well as material scientist closely collaborate.