Ultrafast Switching in a Phase-Change Material

Chalcogenide compounds are phase-change materials used in some types of rewriteable DVDs. The materials’ phase change—between an amorphous glass and an ordered crystal—relies on a separate electrical change: a field-induced drop in resistance, called “threshold switching.” To explore how fast this switching occurs, researchers exposed a chalcogenide compound to electrical pulses that were shorter than those previously tested. They found that threshold switching occurs on subpicosecond scales, suggesting chalcogenides have a future in ultrafast memory devices and switches.