Local structure and influence of bonding on the phase-change behavior of the chalcogenide compounds K1-xRbxSb5S8

J. B. Wachter, K. Chrissafis, V. Petkov, C. D. Malliakas, D. Bilc, Th Kyratsi, K. M. Paraskevopoulos, S. D. Mahanti, T. Torbrügge, H. Eckert, M. G. Kanatzidis

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

KSb5S8 and its solid solution analogs with Rb and Tl were found to exhibit a reversible and tunable glass→crystal→glass phase transition. Selected members of this series were analyzed by differential scanning calorimetry to measure the effect of the substitution on the thermal properties. The solid solutions K1-xRbxSb5S8 exhibited clear deviations in melting and crystallization behavior and temperatures from the parent structure. The crystallization process of the glassy KSb5S8 as a function of temperature could clearly be followed with Raman spectroscopy. The thermal conductivity of both glassy and crystalline KSb5S8 at room temperature is ∼0.40 W/m K, among the lowest known values for any dense solid-state material. Electronic band structure calculations carried out on KSb5S8 and TlSb5S8 show the presence of large indirect band-gaps and confirm the coexistence of covalent Sb-S bonding and predominantly ionic K(Tl)⋯S bonding. Pair distribution function analyses based on total X-ray scattering data on both crystalline and glassy K1-xRbxSb5S8 showed that the basic structure-defining unit is the same and it involves a distorted polyhedron of "SbS7" fragment of ∼7 Å diameter. The similarity of local structure between the glassy and crystalline phases accounts for the facile crystallization rate in this system.

Original languageEnglish
Pages (from-to)420-431
Number of pages12
JournalJournal of Solid State Chemistry
Volume180
Issue number2
DOIs
Publication statusPublished - Feb 1 2007

Keywords

  • Glasses
  • Non-volatile memory

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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