Hu, C: Interplay of spins, charges and photons in low-dimens

This Habilitationsschrift is based on 20 selected papers published/submitted after I joined the University of Hamburg on September 2, 1999, which include 2 invited ones, 16 others published in Physical Review Letters, Europhysics Letters, Physical Review B, Applied Physics Letters, and 2 preprints. Three papers on spintronics are based on experiments performed before I joined the Universität Hamburg. Writing the work provides me a chance to look back over my past five and a half year¿s academic life in Hamburg, where I have enjoyed and appreciated the hospitality of my colleagues in the Institut für Angewandte Physik of Universität Hamburg. The Habilitationsschrift begins with this general introduction followed by a list of papers on three seemingly different topics: spintronics, photoconductivity, and the bilayer two-dimensional electron system. The work covers three different materials, namely semiconductors, ferromagnetic metals, and their hybrid samples. They are experimentally investigated by three different techniques: magneto- and spin-dependent transport, far-infrared transmission spectroscopy, as well as microwave and infrared photoconductivity spectroscopy. Cross thinking of different systems vs various techniques has been a convenient source of developing new ideas for performing experiments. At the heart of the topics which I have been absorbed over the years is the interplay between spins, charges, and photons in low-dimensional electron systems. The Habilitationsschrift is organized in five chapters: spin-orbit coupling, spin-charge conversion in transport, spin-charge mixing in spectroscopy, electron-electron interaction, electron-phonon interaction.