TY - JOUR
T1 - Phase-change materials
T2 - The view from the liquid phase and the metallicity parameter
AU - Wei, Shuai
AU - Lucas, Pierre
AU - Angell, C. Austen
N1 - Funding Information:
P.L. acknowledges financial support from the National Science Foundation (NSF)-Division of Materials Research under Grant No. 1832817. C.A.A. acknowledges financial support from NSF Chemistry Division under Grant Nos. CHE-1213265 and CHE-185606. S.W. is grateful for discussion with P. Zalden and comments of M. Wuttig.
Publisher Copyright:
© 2019 Materials Research Society.
PY - 2019/9/1
Y1 - 2019/9/1
N2 - While fast-switching rewritable nonvolatile memory units based on phase-change materials (PCMs) are already in production at major technology companies such as Intel (16-64 GB chips are currently available), an in-depth understanding of the physical factors that determine their success is still lacking. Recently, we have argued for a liquid-phase metal-to-semiconductor transition (M-SC), located not far below the melting point, Tm, as essential. The M-SC is itself a consequence of atomic rearrangements that are involved in a fragile-to-strong viscosity transition that controls both the speed of crystallization and the stabilization of the semiconducting state. Here, we review past work and introduce a new parameter, the "metallicity" (inverse of the average Pauling electronegativity of a multicomponent alloy). When Tm -scaled temperatures of known M-SCs of Group IV, V, and VI alloys are plotted against their metallicities, the curvilinear plot leads directly to the composition zone of all known PCMs and the temperature interval below Tm, where the transition should occur. The metallicity concept could provide guidance for tailoring PCMs.
AB - While fast-switching rewritable nonvolatile memory units based on phase-change materials (PCMs) are already in production at major technology companies such as Intel (16-64 GB chips are currently available), an in-depth understanding of the physical factors that determine their success is still lacking. Recently, we have argued for a liquid-phase metal-to-semiconductor transition (M-SC), located not far below the melting point, Tm, as essential. The M-SC is itself a consequence of atomic rearrangements that are involved in a fragile-to-strong viscosity transition that controls both the speed of crystallization and the stabilization of the semiconducting state. Here, we review past work and introduce a new parameter, the "metallicity" (inverse of the average Pauling electronegativity of a multicomponent alloy). When Tm -scaled temperatures of known M-SCs of Group IV, V, and VI alloys are plotted against their metallicities, the curvilinear plot leads directly to the composition zone of all known PCMs and the temperature interval below Tm, where the transition should occur. The metallicity concept could provide guidance for tailoring PCMs.
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U2 - 10.1557/mrs.2019.207
DO - 10.1557/mrs.2019.207
M3 - Article
AN - SCOPUS:85072048918
SN - 0883-7694
VL - 44
SP - 691
EP - 698
JO - MRS Bulletin
JF - MRS Bulletin
IS - 9
ER -