| Objectives: The prime goal of this FOM programme is to create, investigate and control novel electronic and magnetic phases, arising from electronic and orbital reconstruction at hetero-interfaces in complex oxides. The concrete objectives of the programme are: I.: To establish a theoretical basis for the identification of the most promising combinations of materials and the understanding of their interface characteristics. II.: The experimental realization of atomically designed interfaces in these materials. III.:The micro-structural and spectroscopic characterization of these interfaces. IV.: The investigation and understanding of their electronic and magnetic transport properties, especially focusing on the occurrence of new phases and the fabrication of novel devices. Background, relevance and implementation: In many ionic materials, such as the complex oxides, surfaces created along specific crystalline directions become electrically polarized. Equally, such electronic polarization can occur at the hetero-interface between two abutting materials. This polarization implies that the electrostatic potential would diverge when moving from the interface into the bulk. As such a divergence is energetically not allowed, this phenomenon is also known as a 'polar catastrophe'. Nature deals with this situation by reconstructing the electronic configuration of the interface. A tantalizing consequence of such an electronic reconstruction is that it provides a means to create, and ultimately to control and exploit, novel electronic and magnetic phases that intrinsically cannot exist in the bulk. Moreover, being bound to the interface, these phases are characterized by a reduced dimensionality, providing a rich basis for exciting new physics. By pulsed laser deposition, interfaces will be realized between complex oxides. These will be studied by microscopy, spectroscopy and transport measurements. In addition, a theoretical basis will be developed to describe their properties and to predict novel features. Such studies will not only greatly enhance the basic understanding of the materials involved, but will also represent important steps in the quest for electronic nano-devices 'beyond Moore'. |
