Physics-Uspekhi

We review the current stage of research of track formation processes and mechanisms in materials irradiated by swift ions. We show that the nature and morphology of tracks depend on the type and structure of the material and on the energy density transfer to its electron subsystem. Swift heavy ions serve as tools to synthesize nanoclusters and nanowires, to controllably change their morphology, and to tailor electronic, magnetic, and optical properties. The unique optical, photoelectric, and conducting properties of tracks can be used to create a new generation of electronic and optoelectronic nanosize devices. These low-dimensional objects exhibit quantum behavior and are stimulating a broad range of fundamental and applied research.