Observation of a reentrant phase transition in incommensurate potassium

L. F. Lundegaard, G. W. Stinton, M. Zelazny, C. L. Guillaume, J. E. Proctor, I. Loa, E. Gregoryanz, R. J. Nelmes, M. I. McMahon

Research output: Contribution to journalArticlepeer-review

Abstract

The phase transitions in the host-guest composite structure of potassium have been determined between 19 and 54 GPa by a combination of x-ray powder and single-crystal diffraction. The guest component of the incommensurate composite phase K-III undergoes an "intraphase" transition at 30.0(7) GPa from a C-centered tetragonal structure to an A-centered orthorhombic form. At 39.7(5) GPa, the guest component undergoes a reentrant transition back to the C-centered tetragonal form. This is the first such reentrant transition observed in the composite structures of the elements. The transition in the guest at 30.0(7) GPa is preceded by a loss of the c-glide symmetry of the host component of the structure, and this is not recovered until some 3 GPa after the reentrant transition at 39.7 GPa.

Original languageEnglish
Article number054106
Number of pages6
JournalPhysical review B: Condensed matter and materials physics
Volume88
Issue number5
DOIs
Publication statusPublished - 14 Aug 2013

Keywords

  • HIGH-PRESSURE
  • SODIUM
  • LITHIUM
  • BARIUM
  • METALS

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