The transition from quantum to classical magnetism investigated by scanning tunneling microscopy

• Applicant: Dr. Kirsten von Bergmann
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2007 to 2008
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 62871544

The magnetic properties of single atoms in the gas phase have been known and measured with high precision for a long time. On the other extreme of length scales, the magnetic properties of bulk magnets are also well understood and have been harnessed for many technological applications such as magnetic data storage in hard disk drives. The inter-mediate regime of a countable number of magnetic atoms coupled to each other through direct or indirect exchange interactions bridges the transition from the quantum to the classical world and has recently led to the exciting discovery of single molecule magnets with novel magnetic properties. In the quantum limit of magnetism the IBM scanning tunneling microscopy (STM) group has recently succeeded in measuring spin excitations of engineered atomic-scale magnetic structures which have yielded detailed information about their ground and excited states. The method of spin-resolved STM has been established over the last years by the group in Hamburg for the investigation of magnetism in nanostructures: one can directly map the spin structure −describable by the classical Heisenberg model− with high spatial resolution. The aim of this proposed project is to study the transition between the quantum and the classical limit of magnetism using STM by combining the strengths of the two above-mentioned approaches of spin excitation and local spin-resolved measurements.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Dr. Andreas J. Heinrich