Ultrafast optical manipulation of atomic arrangements in chalcogenide alloy memory materials

Opt Express. 2011 Jan 17;19(2):1260-70. doi: 10.1364/OE.19.001260.

Abstract

A class of chalcogenide alloy materials that shows significant changes in optical properties upon an amorphous-to-crystalline phase transition has lead to development of large data capacities in modern optical data storage. Among chalcogenide phase-change materials, Ge2Sb2Te5 (GST) is most widely used because of its reliability. We use a pair of femtosecond light pulses to demonstrate the ultrafast optical manipulation of atomic arrangements from tetrahedral (amorphous) to octahedral (crystalline) Ge-coordination in GST superlattices. Depending on the parameters of the second pump-pulse, ultrafast nonthermal phase-change occurred within only few-cycles (≈1 picosecond) of the coherent motion corresponding to a GeTe4 local vibration. Using the ultrafast switch in chalcogenide alloy memory could lead to a major paradigm shift in memory devices beyond the current generation of silicon-based flash-memory.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alloys / chemistry*
  • Alloys / radiation effects*
  • Chalcogens / chemistry*
  • Chalcogens / radiation effects*
  • Lasers*

Substances

  • Alloys
  • Chalcogens