A high-pressure phase with a non-centrosymmetric crystal structure in the PbSe–PbBr2 system

Danrui Ni, Shu Guo, Kelly M. Powderly, Ruidan Zhong, Robert J. Cava

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1 Scopus citations

Abstract

We report Pb3Se2Br2, a lead chalcogenide halide that has not been described in the ambient pressure PbSe–PbBr2 system, synthesized using a high-pressure solid-state method at 4 GPa and 700 °C. Its crystal structure is determined by single crystal X-ray diffraction to be body centered cubic and non-centrosymmetric (Th3P4 structure type, space group I4‾3d, #220) with a = 9.3200(4) Å at room temperature and ambient pressure, where it appears to be a metastable phase. The Pb atoms are coordinated by eight anions in a dodecahedron, with Se and Br occupying the same crystallographic site in a disordered 1:1 ratio to yield a normal valence compound. Pb3Se2Br2 is a semiconductor with an indirect band gap of 1.48 eV, determined by diffuse reflectance measurements. The indirect band gap is theoretically supported by density functional theory calculations.

Original languageEnglish (US)
Article number120982
JournalJournal of Solid State Chemistry
Volume280
DOIs
StatePublished - Dec 2019

All Science Journal Classification (ASJC) codes

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

Keywords

  • High pressure synthesis
  • Lead chalcogenide halide
  • Non-centrosymmetric structure
  • Single crystal X-ray diffraction
  • Solid state reaction

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