Ultrafast phase transition dynamics in GeSb alloys

Abstract

Summary form only given. There has been a considerable research effort on laser-induced phase transitions in Sb-rich alloys since the late 1980s. Thin films of GeSb allow optically-induced, optically-reversible, crystalline to amorphous phase transitions that are both very fast (ns) and are accompanied by a large reflectivity change (up to 20%). In 1998, Sokolowski-Tinten et al. reported evidence of an ultrafast (200 fs) transition of amorphous GeSb to the crystalline phase. We present the most thorough experimental study to date of laser-induced ultrafast phase transitions in GeSb alloys. We monitor changes in the full dielectric function over a broad energy range following excitation by an pump pulse.