Reference : Near Kohn anomalies in the phonon dispersion relations of lead chalcogenides
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
http://hdl.handle.net/10993/8264
Near Kohn anomalies in the phonon dispersion relations of lead chalcogenides
English
Kilian, Ondrej [Department of Astronomy, Physics of the Earth, and Meteorology, Comenius University, Slovakia / Institute for Electronics, Microelectronics, and Nanotechnology (IEMN), Department ISEN, CNRS-UMR 8520, France]
Allan, Guy [CNRS-UMR 8520 > Department ISEN > Institute for Electronics, Microelectronics, and Nanotechnology]
Wirtz, Ludger mailto [CNRS-UMR 8520 > Department ISEN > Institute for Electronics, Microelectronics, and Nanotechnology (IEMN)]
2009
Physical Review B
80
24
Yes (verified by ORBilu)
International
1098-0121
[en] We present ab initio phonon dispersion relations for the three lead chalcogenides PbS, PbSe, and PbTe. The acoustic branches are in very good agreement with inelastic neutron-scattering data and calculations of the specific heat give good agreement with experimental data. The pronounced minimum of the transverse-optical branch at Gamma due to the near ferroelectricity of the lead chalcogenides is qualitatively reproduced. In addition, we find a pronounced dip in the longitudinal-optical branch at Gamma. This dip was previously explained as the effect of "free carriers" (due to the presence of impurities). The calculations demonstrate that it persists also in the case of pure lead chalcogenides. We explain the dip as a "near Kohn anomaly" which is associated with the small electronic band gap at the high-symmetry point L.
http://hdl.handle.net/10993/8264
10.1103/PhysRevB.80.245208

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