Comparison of different modeling approaches for thermoelectric elements

We model and evaluate the Peltier and Seebeck effects in magnetic multilayer nanostructures by a finite-element theory of thermoelectric properties. We present analytical expressions for the thermopower and the current-induced temperature changes due to Peltier cooling/heating. The thermopower of a magnetic element is in general spin polarized, leading to spin-heat coupling effects. Thermoelectric effects in spin valves depend on the relative alignment of the magnetization directions and are sensitive to spin-flip scattering as well as inelastic collisions in the normal-metal spacer.

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Thermoelectric effects in magnetic nanostructures

A numerical study on the performance of miniature thermoelectric cooler affected by Thomson effect

Experimental study on thermoelectric modules for power generation at various

http://profdoc.um.ac.ir/articles/a/1015558.pdf

Fe-doped SnO2 transparent semi-conducting thin films deposited by spray pyrolysis technique: Thermoelectric and p-type conductivity properties

The thermo-emf in bipolar semiconductors is calculated. It is shown that it is necessary to take into account the nonequilibrium distribution of electron and hole concentrations (Fermi quasilevels of the electrons and holes). We find that electron and hole electric conductivities of contacts of semiconductor samples with connecting wires make a substantial contribution to thermo-emf.

Nature of the thermopower in bipolar semiconductors.

A new approach is suggested to explain the Peltier effect. It assumes that the Peltier effect is not an isothermal effect. The approach is based on the occurrences of induced thermal fluxes in a structure which consists of two conducting media, through which a dc electric current flows. These induced thermal diffusion fluxes arise to compensate for the change in the thermal flux caused by the electric current (the drift thermal flux) flowing through the junction, in accordance with the general Le Chprinciple. The occurrence of these thermal diffusion fluxes leads to temperature heterogeneity in the structure and, as a result, to a cooling or heating of the junction. Within the framework of this concept, the thermoelectric cooling is analysed. It is shown that in the general case the Peltier effect always occurs together with another thermoelectric effect. This thermoelectric effect is predicted for the first time, and we have called it the barrierless thermoelectric effect. Both these effects essentially depend on the junction surface thermal resistance. The Peltier effect disappears in the limiting case of a very large surface thermal resistance, while the barrierless effect disappears in the limiting case of a very small surface thermal resistance. The dependence of thermoelectric cooling on the geometrical dimensions of the structure is noted, and the corresponding interpretation of this fact is discussed. It is shown that the thermoelectric cooling (heating) is a thermodynamically reversible process in the linear approximation of the electric current applied.

https://iopscience.iop.org/article/10.1088/0268-1242/20/12/R01/pdf

Physics of thermoelectric cooling

A new approach to thermoelectric phenomena, as a linear transport process of non-equilibrium charge carriers, is presented. The role of non-equilibrium carriers, as well as surface and bulk recombination, is demonstrated to be crucial even within a linear approximation. Electron and hole Fermi quasi-levels appeared in a thermal field are calculated in the case of thermoelectric current flow through a circuit. It is shown, for the first time, that the Fermi quasi-level of one of subsystem of quasi-particles can be a non-monotonic function of the coordinates. General expressions for the thermoelectric current, thermo-e.m.f., and electrical resistance of bipolar semiconductors have been obtained. For the first time the surface recombination and surface resistance were taken into account.

The Role of Non-Equilibrium Carriers in Formation of Thermo-E.M.F. in Bipolar Semiconductors

The effective thermal conductivity and thermal diffusivity of a two-layer system are investigated from the theoretical point of view for application to photoacoustic experiments. The effective thermal parameters are obtained by comparing the temperature distribution on the left or right surface of the layered structure and some effective one-layer material. These effective thermal parameters are calculated for some special cases as for example, low and high chopper frequency. The influence of the interface thermal contact between the layers plays an important role on the effective thermal parameters. It is shown that the effective thermal conductivity and thermal diffusivity depend strongly upon the used photothermal technique.

Heat Diffusion in Two-Layer Structures: Photoacoustic Experiments

A comprehensive study of the mechanisms of heating and cooling originated by an electrical current in semiconductor devices is reported. The authors studied the Peltier, Joule, and Thomson phenomena self-consistently and found that the magnitudes of all of them were commensurable. A new formulation and interpretation of the Thomson effect are offered. The main conclusion of the present work is that the thermal analysis of any semiconductor device under real working conditions demands the inclusion of all heating and cooling mechanisms simultaneously.

G. N. Logvinov

Papers

Nature of the thermopower in bipolar semiconductors.

Physics of thermoelectric cooling

The Role of Non-Equilibrium Carriers in Formation of Thermo-E.M.F. in Bipolar Semiconductors

Heat Diffusion in Two-Layer Structures: Photoacoustic Experiments

Heating and cooling in semiconductor structures by an electric current