Electronic Transport in Alloys with Phase Separation (Composites)  

作　　者：Joachim Sonntag Bertrand Lenoir Pawel Ziolkowski 

机构地区：[1]TE Connectivity Sensors Germany GmbH, Dortmund, Germany [2]Institut Jean Lamour, UMR 7198 CNRS-Université de Lorraine, 2 Allée André Guinier-Campus ARTEM, Nancy Cedex, France [3]German Aerospace Center, Institute of Materials Research, Koln, Germany

出　　处：《Open Journal of Composite Materials》2019年第1期21-56,共36页复合材料期刊（英文）

摘　　要：A measure for the efficiency of a thermoelectric material is the figure of merit defined by ZT = S2T/ρκ, where S, ρ and κ are the electronic transport coefficients, Seebeck coefficient, electrical resistivity and thermal conductiviy, respectively. T is the absolute temperature. Large values for ZT have been realized in nanostructured materials such as superlattices, quantum dots, nanocomposites, and nanowires. In order to achieve further progress, (1) a fundamental understanding of the carrier transport in nanocomposites is necessary, and (2) effective experimental methods for designing, producing and measuring new material compositions with nanocomposite-structures are to be applied. During the last decades, a series of formulas has been derived for calculation of the electronic transport coefficients in composites and disordered alloys. Along the way, some puzzling phenomenons have been solved as why there are simple metals with positive thermopower? and what is the reason for the phenomenon of the “Giant Hall effect”? and what is the reason for the fact that amorphous composites can exist at all? In the present review article, (1), formulas will be presented for calculation of σ = (1/ρ), κ, S, and R in composites. R, the Hall coefficient, provides additional informations about the type of the dominant electronic carriers and their densities. It will be shown that these formulas can also be applied successfully for calculation of S, ρ, κ and R in nanocomposites if certain conditions are taken into account. Regarding point (2) we shall show that the combinatorial development of materials can provide unfeasible results if applied noncritically.A measure for the efficiency of a thermoelectric material is the figure of merit defined by ZT = S2T/ρκ, where S, ρ and κ are the electronic transport coefficients, Seebeck coefficient, electrical resistivity and thermal conductiviy, respectively. T is the absolute temperature. Large values for ZT have been realized in nanostructured materials such as superlattices, quantum dots, nanocomposites, and nanowires. In order to achieve further progress, (1) a fundamental understanding of the carrier transport in nanocomposites is necessary, and (2) effective experimental methods for designing, producing and measuring new material compositions with nanocomposite-structures are to be applied. During the last decades, a series of formulas has been derived for calculation of the electronic transport coefficients in composites and disordered alloys. Along the way, some puzzling phenomenons have been solved as why there are simple metals with positive thermopower? and what is the reason for the phenomenon of the “Giant Hall effect”? and what is the reason for the fact that amorphous composites can exist at all? In the present review article, (1), formulas will be presented for calculation of σ = (1/ρ), κ, S, and R in composites. R, the Hall coefficient, provides additional informations about the type of the dominant electronic carriers and their densities. It will be shown that these formulas can also be applied successfully for calculation of S, ρ, κ and R in nanocomposites if certain conditions are taken into account. Regarding point (2) we shall show that the combinatorial development of materials can provide unfeasible results if applied noncritically.

关 键 词：HALL EFFECT Giant HALL EFFECT SEEBECK Coefficient (Thermopower) Electron Density CONDUCTIVITY Thermal CONDUCTIVITY COMPOSITES Nanocomposites Percolation Theory 

分 类 号：R73[医药卫生—肿瘤]