Defect formation in insulators under dense electronic excitation

Defect formation in insulators induced by electronic excitation is reviewed, emphasizing possible role on formation of tracks of heavy ions. Relaxation of excitons that produces selftrapped excitons and defects is discussed first. Evidence for defect formation by interaction of a selftrapped excitons with another excitation event is described. It is pointed out that track registration has been observed so far only in materials in which excitons are selftrapped. It is suggested that track registration occurs though interaction of selftrapped excitons among each other or with other excitation events.