Thermal conductivity of doped PbTe-based solid solutions with off-center impurities
- Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)
- St. Petersburg State Polytechnical University (Russian Federation)
The coefficients of thermopower and electrical and thermal conductivity in the PbTe{sub 0.8}Se{sub 0.1}S{sub 0.1} solid solution with electron concentration (4.6-54) x 10{sup 18} cm{sup -3} are studied in the range of 85-300 K (and in some cases up to 700 K). The temperature dependences of electrical and thermal conductivity indicate that the low-temperature electron and phonon scattering initiated by the off-center impurity of sulfur exists. The temperature dependences of the electronic and lattice components of thermal conductivity are calculated in the approximation of a parabolic spectrum and electron scattering by acoustic phonons and neutral substitutional impurities. The lattice thermal conductivity is found to have a feature in the form of a shallow minimum in the range of 85-250 K. A similar feature, while not so clearly pronounced, is found to exist also in Pb{sub 1-x}Sn{sub x}Te{sub 1-x}Se{sub x} alloys (x{>=}0.15) with an off-center tin impurity. An analysis of the possible origins of this effect suggests that, at low temperatures, the Lorentz numbers L of the materials under study are smaller than the L{sub 0} numbers employed which correspond to the above scattering mechanisms. The cause of the decrease in L is related to electron scattering at two-level systems, a mechanism whose effect grows with increasing electron energy. An analysis of experimental data obtained at high temperatures, as well as on undoped samples with the lowest possible carrier concentrations, yields the values of L for samples with different electron densities. The minimum value L/L{sub 0} = 0.75 is obtained for a lightly doped sample at {approx}130 K.
- OSTI ID:
- 21088516
- Journal Information:
- Semiconductors, Vol. 40, Issue 7; Other Information: DOI: 10.1134/S1063782606070037; Copyright (c) 2006 Nauka/Interperiodica; Article Copyright (c) 2006 Pleiades Publishing, Inc; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7826
- Country of Publication:
- United States
- Language:
- English
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