Multistates and Polyamorphism in Phase-Change K₂Sb₈Se₁₃
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.
S. M. Islam and L. Peng and L. Zeng and C. D. Malliakas and D. Y. Chung and D. B. Buchholz and T. Chasapis and R. Li and K. Chrissafis and J. E. Medvedeva and For full list of authors, see publisher's website., "Multistates and Polyamorphism in Phase-Change K₂Sb₈Se₁₃," Journal of the American Chemical Society, vol. 140, no. 29, pp. 9261 - 9268, American Chemical Society (ACS), Jul 2018.
The definitive version is available at https://doi.org/10.1021/jacs.8b05542
Center for High Performance Computing Research
Keywords and Phrases
Antimony compounds; Computation theory; Computer circuits; Crystalline materials; Digital storage; Logic devices; Optical data storage; Optical switches; Phase change materials; Reconfigurable hardware; Selenium compounds, Amorphous-amorphous transition; Crystal phase transition; Crystal transition; Electrical conductivity; Orders of magnitude; Polyamorphic transitions; Reconfigurable logic; Solid-state materials, Amorphous materials, article; crystal; electric conductivity; logic; room temperature
International Standard Serial Number (ISSN)
Article - Journal
© 2018 American Chemical Society (ACS), All rights reserved.
01 Jul 2018
SMI, LP, LZ, DDB, VDP, MG, TJM, MGK, MJB, RL and JEM acknowledge support from the MRSEC program (NSF DMR-1720139) at the Materials Research Center.