Phase-change materials: The view from the liquid phase and the metallicity parameter

Shuai Wei, Pierre Lucas, C. Austen Angell

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)691-698
Number of pages8
JournalMRS Bulletin
Issue number9
StatePublished - Sep 1 2019

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry


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