LaSe2-x compounds: Vibrational and electrical properties

Andrzej Grzechnik, Jian Zhi Zheng, David Wright, William Petuskey, Paul F. McMillan

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

The phase diagram in the system La-Se was investigated around the LaSe2 composition. X-ray and microprobe analyses reveal the existence of only two phases, LaSe2 and LaSe1.9, with no solid solution behavior between them. Infrared and Raman spectra of the non-stoichiometric phase suggest that the vacancies in the basal plane of the low-dimensional lattice are disordered. Polarized single crystal Raman spectra and a modified valence force field calculation for LaSe2 indicate that the assumption of isolated (Se-Se)2- pairs in the anti-Fe2As structure is not justified. In accord with this, the observed resistivity for LaSe2 as a function of temperature is typical of a semimetallic compound. A transition to a semiconductor may occur below 110K. The measured resistivity as a function of temperature for the non-stoichiometric LaSe1.9 phase is indicative of a semiconductor. The infrared data together with the electrical measurements suggest that this phase can be considered as n-type semiconductor with the holes in the anionic sp valence bands.

Original languageEnglish (US)
Pages (from-to)1625-1634
Number of pages10
JournalJournal of Physics and Chemistry of Solids
Volume57
Issue number11
DOIs
StatePublished - Nov 1996

Keywords

  • A. chalcogenides
  • C. Raman spectroscopy
  • C. infrared spectroscopy
  • D. crystal structure
  • D. electrical properties

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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