This volume contains the invited papers of the Spring meeting of the Arbeitskreis Festkörperphysik of the Deutsche Physikalische Gesellschaft, which has been held in Regensburg in the period March 23 - 27, 1998. The meeting has been attended by more than 2800 participants from all areas of solid state physics and other areas of physics as well since this time it has been organized together with the yearly general meeting. The invited and plenary talks as well as the numerous symposia reflected most recent developments in physics. This book covers the current status of the fileds and shows the excitement which has been felt by the speakers when presenting their results.

Present status of InGaN-based UV/blue/green LEDs and laser diodes.- Group III-nitride based blue emitters.- Laser processes in group-III nitrides.- Growth and characterization of II-VI semiconductor lasers.- Many-body theory for II-VI semiconductor laser media.- SiC: Polar properties and their influence on technology and devices.- Growth mechanisms of SiC on ?-SiC(0001) prepared by solid-source molecular beam epitaxy.- Si1?x?yGexCy alloys: Growth and properties of a new semiconducting material.- Correlations between microstructure and electronic properties in amorphous carbon based materials.- Characterization of CVD-diamond layers: Electronic states.- Electron ground states in a few-electron quantum dot.- Atomically precise, coupled quantum dots fabricated by cleaved edge overgrowth.- Raman spectroscopy of quantum dots.- Charged excitons in InAs quantum dots.- Charge fluctuations, chaotic trajectories, and the coulomb blockade.- Diode lasers based on quantum dots.- Sonoluminescence: When bubbles glow.- Bloch oscillations in semiconductor superlattices.- Optical properties of localized excitons in nanostructures: Theoretical aspects.- Superradiant exciton-light coupling in semiconductor heterostructures-Theory.- Superradiant exciton/light coupling in semiconductor heterostructures-Part II: Experiments.- Quantum kinetics in semiconductors: Experiments on a 10-femtosecond timescale.- Theory for semiconductor near-field optics: Selection rules and coherent spatio-temporal dynamics.- Near-field scanning optical spectroscopy of semiconductor nanostructures.- Lorentz microscopic investigations of micromagnetic structures.- Optical and mobility measurements of alkali earth atoms and ions in superfluid helium.- Disorder and impurities in hubbard-antiferromagnets.-Metallic ferromagnetism: Progress in our understanding of an old strong-coupling problem.- Interacting electrons in a narrow quantum hall system.- Electron-electron interaction effects in single-wall carbon nanotubes.- A new look at low-temperature anomalies in glasses.- Disorder phenomena in chaotic systems.- Zero bias anomalies in the tunneling spectra of high temperature superconductors.- Superconductivity in fullerene compounds.- Heteroepitaxy and noise in integrated HTS dc-SQUID magnetometers.- Magnetic phase diagram and reentrant superconductivity in DyNi2B2C.- The current-phase relation in HTS Josephson junctions.- Cherenkov radiation from Josephson fluxons.- SO(5) symmetry in t-J and hubbard models.- HTS cables for electric power transmission: Basic properties - State of the art - Prospects.- Basic science and challenges in process simulation.- Adaptive cooling on the basis of pulse tube refrigerators.- Current issues in mechanics of layer systems for sensors and actuators.- The crystalline silicon thin-film solar cell-The high temperature approach.- Thin films for gas sensors in new application fields - MBRS studies and semiempirical calculations.