Applications of radioactive ion beams to solid-state physics

Radioactive atoms have been used in solid-state physics and in material science for many decades. Besides their classical application as tracer for diffusion studies, nuclear techniques such as Mofibauer spectroscopy, perturbed angular correlation, β-NMR, and emission channeling have used nuclear properties (via hyperfine interactions or emitted α- or β-particles) to gain microscopical information on the structural and dynamical properties of solids. During the last decade, the availability of many different radioactive isotopes as a clean ion beam at ISOL facilities like ISOLDE/CERN has triggered a new era involving methods sensitive for the optical and electronic properties of solids, especially in the field of semiconductor physics. Extremely sensitive spectroscopic techniques like deep-level transient spectroscopy (DLTS), photoluminescence (PL), and Hall effect gain a new quality by using radioactive isotopes: Due to their decay the chemical origin of an observed electronic and optical behavior of a specific defect or dopant can be unambiguously identified. This review will briefly introduce the experimental techniques used and browse through the ongoing experiments in solid-state physics using radioactive ion beams demonstrating the wide variety of problems under study involving bulk properties, surfaces and interfaces in many different systems like semiconductors, superconductors, magnetic systems, metals and ceramics.