Syntheses, crystal and electronic structure, and some optical and transport properties of LnCuOTe (Ln=La, Ce, Nd)

Min Ling Liu, Li Bin Wu, Fu Qiang Huang*, Li Dong Chen, James A. Ibers

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

48 Scopus citations

Abstract

Three new compounds, LaCuOTe, CeCuOTe, and NdCuOTe, have been synthesized from the respective rare-earth elements, CuO, and a KI flux at 1023 K. The compounds, which have the ZrSiCuAs structure type, are isostructural to LaCuOS, and crystallize in space group P4/nmm of the tetragonal system with two formula units in cells of dimensions at 153 K of a = 4.1775 (5) Å, c = 9.3260 (16) Å, V = 162.75 (4) Å3 for LaCuOTe; a = 4.1497 (3) Å, c = 9.3090 (10) Å, V = 160.30 (2) Å3 for CeCuOTe; and a = 4.1056 (9) Å, c = 9.332 (4) Å, V = 157.30 (8) Å3 for NdCuOTe. The structure of LnCuOTe (Ln=La, Ce, Nd) is composed of alternating PbO-like [Ln2O2] and anti-PbO-like [Cu2Te2] layers stacked perpendicular to [0 0 1]. The experimental optical band gaps of LaCuOTe and NdCuOTe are 2.31 and 2.26 eV, respectively. At 298 K the electrical conductivity of LaCuOTe is 1.65 S/cm and the Hall mobility is +80.6 cm2 V-1 s-1. The positive values of the Seebeck and Hall coefficients indicate p-type electrical conduction. First-principles theoretical calculations were performed on LaCuOQ (Q=S, Se, Te). In LaCuOTe, Cu 3d and Te 5p orbitals dominate the states near the valence band maximum; the states near the conduction band minimum are composed of Cu 4s, Te 5p, and La 5d orbitals. The larger dispersion of Cu 3d orbitals and the presence of Te 5p orbitals near the valence band maximum are responsible for the larger hole mobility of LaCuOTe compared to LaCuOS and LaCuOSe.

Original languageEnglish (US)
Pages (from-to)62-69
Number of pages8
JournalJournal of Solid State Chemistry
Volume180
Issue number1
DOIs
StatePublished - Jan 2007

Keywords

  • Crystal structure
  • Electronic structure
  • Optical properties
  • Rare-earth copper oxytelluride
  • Transport properties

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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