FOR 1162:  Electron Correlation-Driven Phenomena in Surfaces and Interfaces with Tunable Interactions

• Subject Area: Physics
• Term: from 2009 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 85460759

Subject of the Research Unit are electronic quantum phenomena in nanoscale structures of novel materials and the exploration of their application potential. The project is carried by nine physicists of the University of Würzburg, supported by two scientists at the Max Planck Institute for Solid State Research in Stuttgart and at RWTH Aachen.
Due to the ever-decreasing length scales of modern microelectronics the electrical repulsion between the charge carriers becomes of increasing importance for device functionality. The resulting quantum effects are even stronger, if the electrons are confined to low (2 or 1) dimensions. While in conventional semiconductor technology this can lead to detrimental effects, in other materials the interelectronic interaction may even be useful for novel and custom-tailored functionalities (e.g., in transition metal oxides or intermetallic Ce-compounds). Therefore, the Research Unit will focus on two issues: (1) the investigation of many-body quantum phenomena in low-dimensional nanoscale model structures (i.e., at surfaces and interfaces) in order to elucidate their underlying microscopic mechanism and (2) their controlled manipulation by, e.g., materials choice or external electrical and magnetic fields. Possible examples for applications are highly sensitive magnetic field detectors, electrically writable magnetic memory or switchable superconductivity.
The Research Unit comprises a wide range of powerful experimental and theoretical methods, employed within nine closely cooperating projects. In good tradition of the Physics Department of Würzburg (W.C. Röntgen discovered the x-rays here in 1896, earning him the first ever Nobel prize in physics), the use of x-ray radiation for modern spectroscopy will play a central role in these activities.

• DFG Programme: Research Units
• International Connection: Austria

Projects

• Charge dynamics of two-dimensional electron gases at surfaces and interfaces (Applicant Pimenov, Andrei )
• Correlation effects in self-organized atomic nanostructures on semiconductor surfaces (Applicant Claessen, Ralph )
• Electronic and vibration excitations of ordered adatom assemblies, studied by optical spectroscopy and electron scattering (Applicant Geurts, Jean )
• Electronic structure and many-body effects in interfaces of oxide heterostructures (Applicant Claessen, Ralph )
• Lattice effects in quasi-2D Kondo systems (Applicant Reinert, Friedrich )
• Local magnetic moments and their interaction in correlated systems at reduced dimensions (Applicant Fauth, Kai )
• Many-body effects in the electronic structure and the superconductivity of adsorbates on semiconductor surfaces (Applicants Hanke, Werner ;  Hankiewicz, Ewelina M. )
• Orbital, spin and charge fluctuations in layered oxide heterostructures (Applicant Sangiovanni, Giorgio )
• Single-particle spectral functions for heavy fermion surface-systems and coupled one-dimensional nanowires (Applicant Assaad, Fakher Fakhry )
• Spin-resolved spectro-microscopy of correlated surface and interface systems (Applicant Bode, Matthias )
• Superconductivity in novel surface and interface electronic systems (Applicants Hanke, Werner ;  Honerkamp, Carsten )
• Zentralprojekt (Applicant Claessen, Ralph )
• Zentralprojekt (Applicant Claessen, Ralph )

• Spokesperson: Professor Dr. Ralph Claessen
• Participating Person: Professor Dr. Alfred Forchel