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The high-pressure α/β phase transition in lead sulphide (PbS)

X-ray powder diffraction and quantum mechanical calculations
  • K. Knorr
  • L. Ehm
  • M. Hytha
  • B. Winkler
  • W. Depmeier

Abstract:

The high-pressure behaviour of PbS was investigated by angular dispersive X-ray powder diffraction up to pressures of 6.8 GPa. Experiments were accompanied by first principles calculations at the density functional theory level. By combining both methods reliable data for the elastic properties of rock-salt type α- and high-pressure β-PbS could be obtained. β-PbS could be determined to crystallise in the CrB-type (B33), with space group Cmcm. The reversible ferro-elastic α/β transition is of first order. It is accompanied by a large volume discontinuity of about 5% and a coexistence region of the two phases. A gliding mechanism of {001} bilayers along one of the cubic 〈110〉 directions governs the phase transition which can be described in terms of group/subgroup relationships via a common subgroup, despite its reconstructive character. The quadrupling of the primitive unit cell indicates a wave vector (0, 0,π/a) on the Δ-line of the Brillouin zone.

PACS. 91.60.Gf High-pressure behaviour – 61.50.Ks Crystallographic aspects of phase transformations; pressure effects – 77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides – 62.20.Dc Elasticity, elastic constants 

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Copyright information

© EDP Sciences, Springer-Verlag 2003

Authors and Affiliations

  • K. Knorr
    • 1
  • L. Ehm
    • 1
  • M. Hytha
    • 1
  • B. Winkler
    • 1
  • W. Depmeier
    • 1
  1. 1.Christian-Albrechts-Universität zu Kiel, Institut für Geowissenschaften, Mineralogie/Kristallographie, Olshausenstr. 40, 24098 Kiel, GermanyDE

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