One-dimensional chain melting in incommensurate potassium

E. E. McBride*, K. A. Munro, G. W. Stinton, R. J. Husband, Richard Briggs, H. -P. Liermann, M. I. McMahon

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Between 19 and 54 GPa, potassium has a complex composite incommensurate host-guest structure which undergoes two intraphase transitions over this pressure range. The temperature dependence of these host-guest phases is further complicated by the onset of an order-disorder transition in their guest chains. Here, we report single-crystal, quasi-single-crystal, and powder synchrotron x-ray diffraction measurements of this order-disorder phenomenon in incommensurate potassium to 47 GPa and 750 K. The so-called chain melting transition is clearly visible over a 22 GPa pressure range, and there are significant changes in the slope of the phase boundary which divides the ordered and disordered phases, one of which results from the intraphase transitions in the guest structure.

Original languageEnglish
Article number144111
Number of pages8
JournalPhysical review B: Condensed matter and materials physics
Volume91
Issue number14
DOIs
Publication statusPublished - 22 Apr 2015

Keywords

  • COMPLEX CRYSTAL-STRUCTURE
  • HIGH-PRESSURE
  • BARIUM-IV
  • HG3-DELTA-ASF6
  • SCATTERING
  • PHASE

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