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Multistates and Polyamorphism in Phase-Change K2Sb8Se13.

Saiful M IslamLintao PengLi ZengChristos D MalliakasDuck Young ChungD Bruce BuchholzThomas ChasapisRan LiKonstantinos ChrissafisJulia E MedvedevaGiancarlo G TrimarchiMatthew GraysonTobin J MarksMichael J BedzykRobert P H ChangVinayak P DravidMercouri G Kanatzidis
Published in: Journal of the American Chemical Society (2018)
The phase-change (PC) materials in the majority of optical data storage media in use today exhibit a fast, reversible crystal → amorphous phase transition that allows them to be switched between on (1) and off (0) binary states. Solid-state inorganic materials with this property are relatively common, but those exhibiting an amorphous → amorphous transition called polyamorphism are exceptionally rare. K2Sb8Se13 (KSS) reported here is the first example of a material that has both amorphous → amorphous polyamorphic transition and amorphous → crystal transition at easily accessible temperatures (227 and 263 °C, respectively). The transitions are associated with the atomic coordinative preferences of the atoms, and all three states of K2Sb8Se13 are stable in air at 25 °C and 1 atm. All three states of K2Sb8Se13 exhibit distinct optical bandgaps, Eg = 1.25, 1.0, and 0.74 eV, for the amorphous-II, amorphous-I, and crystalline versions, respectively. The room-temperature electrical conductivity increases by more than 2 orders of magnitude from amorphous-I to -II and by another 2 orders of magnitude from amorphous-II to the crystalline state. This extraordinary behavior suggests that a new class of materials exist which could provide multistate level systems to enable higher-order computing logic circuits, reconfigurable logic devices, and optical switches.
Keyphrases
  • room temperature
  • solid state
  • ionic liquid
  • high resolution
  • dna damage
  • machine learning
  • deep learning
  • artificial intelligence
  • electronic health record