Strange new materials experimentally identified just a few years ago are now driving research in condensed-matter physics around the world. Tthese "strong 3-D topological insulators" - TIs for short - are seemingly mundane semiconductors with startling properties. Topological insulators offer unique opportunities to control electric currents and magnetism, and are promising materials for future spintronic applications or could provide access to novel, fascinating physical phenomena. While so far, only synthetic TIs had been experimentally identified, researchers in Germany report the discovery of a natural occurring topological insulator: the mineral Kawazulite.
A control over spin-electron interactions is vital for development of spintronic devices and for quantum computation. When a magnetic impurity is surrounded by free electrons, a realignment of the electron spins occurs below a critical temperature due to spin-electron interactions; this causes an increase in resistivity of the material - a phenomenon known as the "Kondo" effect. The Kondo effect has been observed in a wide range of systems including single atoms/molecules, quantum-dots, and carbon nanotubes, however two-dimensional molecular Kondo systems have yet to be explored. Molecules with magnetic properties recently have great appeal as they offer an ideal platform to advance the fundamental understanding of spin related mechanisms, and can act as templates for molecular spintronic device fabrication due to their propensity for spontaneous self assembly. By manipulating nearest-neighbor molecules with a scanning tunneling microscope tip researchers now were able to tune the spin-electron coupling of the center molecule inside a small hexagonal molecular assembly in a controlled step-by-step manner. This variation of Kondo effect might be useful for instance for storing or manipulating data in spintronic memory devices.
Researchers have developed an original process to investigate the spin transport properties of a single nanoparticle and provided evidence for its successful realization. This new approach paves the way for a more in-depth study of magneto-Coulomb phenomena in nanosized clusters. While only two results are available up to now on connecting a 0D nano-object to ferromagnetic electrodes enabling spin polarized injection and detection, extensive theoretical studies have been undertaken, leaving the field wide open for experiments.
A recent study shows that just by changing the structure of a molecule, without altering its chemical composition, can lead to a variation in the spin-electron interaction strength, and consequently the associated Kondo temperatures.