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Temperature Dependence of the Vibrational Properties of PbI 2
Author(s) -
Julien C.,
Mavi H. S.,
Chévy A.
Publication year - 1993
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221770110
Subject(s) - anharmonicity , semiconductor , phonon , infrared , ionic bonding , reflection (computer programming) , reflectivity , wavelength , materials science , condensed matter physics , coupling (piping) , optics , chemistry , physics , optoelectronics , quantum mechanics , ion , computer science , programming language , metallurgy
Infrared reflectivity measurements are made from 20 to 600 cm −1 at temperatures ranging from 5 to 575 K for the layered semiconductor PbI 2 . The reflection spectra are analysed by means of a damped Lorentzian‐oscillator model and the calculated optical properties are presented. The infrared reflectivity of PbI 2 shows a broad reststrahlen band, pointing to the significantly ionic character of this compound. Optical properties are compared with those of other layered semiconductors. The optical constants, long‐wavelength optical‐phonon frequencies (both TO and LO), and their half‐widths are obtained as functions of temperature. The temperature dependence is discussed using an anharmonic coupling model with a two‐phonon decay. The general behaviour of anharmonic effects in PbI 2 agrees qualitatively with the theory of Maradudin and Fein.