ABSTRACT
Transport in mesoscopic hybrid structures involving a metallic system and a high-mobility low-dimensional electron system (IDES or 2DES) is of great current interest in both, applied and basic research. Investigations have been performed on hybrid structures consisting of a low-dimensional electron system and, for example, a noble metal [1], a superconductor [2 ] and a ferromagnet [3-5]. In the first case, very recently the extraordinary magnetoresistance effect [6] has been observed. This intriguing effect is based on the magnetic-field induced redistribution of current between the two classes of materials [1,7]. In hybrid structures with a superconductor, where Cooper pairs are injected into a low-dimensional electron system, new and fascinating transport phenomena have been predicted and observed [2]. In both types of hybrid structures, theoretical models based on bulk properties of the two classes of materials have been found to be very successful to explain experimental features. In case of ferromagnet/semiconductor hybrid structures, however, where spin-polarized electrons are injected into a low-dimensional electron system, it has been inferred from, both, theoretical and experimental studies that for spin transport phenomena interfacial properties are inherently important [5].
