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Keywords:

  • 71.20.Nr;
  • 78.20.Ci;
  • 78.40.Fy

Abstract

The optical properties in terms of dielectric function ϵ (ħω) = ϵ1(ħω) + 2(ħω) of rocksalt Pb1–xSnx Te alloys (0 ≤ x ≤ 1) are investigated experimentally by spectroscopic ellipsometry and theoretically by first-principles electronic band structure calculation. We find a strong optical response in the 0.5–2.0 eV region arising from optical absorption around the LW-line of the Brillouin zone. The response peak of the imaginary part of the dielectric functions at E = 1.6–1.8 eV shifts towards lower energies for high Sn compositions as a consequence of narrower W-point band-gap Eg(W) for the Sn-rich alloys. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)