Solid solution Pb_1−xEu_xTe: constitution and thermoelectric behavior

Abstract

The thermoelectric properties of polycrystalline materials on the basis of the solid solution Pb1−xEuxTe prepared by spark-plasma-sintering are characterized. The solid solution undergoes a metal–semiconductor transition in parallel to the p–n transition around 500 K.

Influence of Nanostructuration on PbTe Alloys Synthesized by Arc-Melting

“…This allows us to calculate a lower limit for the figure of merit of this material, using the thermal conductivity at room temperature (1.6 W/mK and 1.28 W/mK for PbTe and LAST, respectively) as well as the power factor for each composition. We obtained a figure of merit of ZT~0.59 at 630 K for PbTe, quite higher than other reported data for pristine PbTe [55,56], but, of course, far from the highest figures of merit reached by other doped lead tellurides. In the case of the LAST compound, the calculated figure of merit was around ZT~0.1 at 580 K, quite lower compared with the best results reported for LAST compounds [30,32].…”

“…At room temperature, the Seebeck coefficient should be positive and then switch to a negative value with increasing temperature [55,56]. We think that the obtained behavior of the Seebeck coefficient for pristine PbTe could occur due to slight evaporation of Te during synthesis.…”

Lattice Softening Significantly Reduces Thermal Conductivity and Leads to High Thermoelectric Efficiency

“…11). In the previous studies [38,39], this dependence was buried in the numerical constants. Thus, the model used herein is able to capture lattice softening effects.…”

“…The lines show a transport model constructed to estimate the relative importance of lattice softening and phonon-scattering in this system. This Callaway-type model has been used previously for Si [38,39], but did not consider changes in speed of sound. In these studies, τ pp is calibrated to single crystalline data and fixed.…”

“…where β is the instrument corrected full width half maximum (in radians), θ is the angle of the diffraction peak, λ is the wavelength of the radiation, C = 4 is a constant related to the nature of the internal strain [28,27,26], and XRD and d XRD are the internal strain and crystallite domain size determined via this Williamson-Hall method. As can be seen in Figure S2c, the {h00} type peaks were significantly sharper than the other peaks [38,54] and were thus excluded from the Williamson-Hall analysis. The resulting least squares fits are shown as lines in Figures 4a and S2c.…”