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TT: Fachverband Tiefe Temperaturen

TT 1: Tutorial: Thermoelectricity – Fundamental Aspects, Materials, Applications (joint session TT/TUT/MA)

TT 1.2: Tutorial

Sunday, March 17, 2024, 16:45–17:25, H 1058

Thermoelectricity: basic concepts, and applications to nanoscale heat engines — •Karol I. Wysokiński — Institute of Physics, M. Curie-Sklodowska University, Lublin, Poland

Thermoelectric power generators directly convert heat into electricity. These solid-state heat engines have no moving parts and are extremely reliable. Their performance is characterized by efficiency and power output, both of which depend on a single parameter called the thermoelectric figure of merit ZT, of which they are monotonically increasing functions. The dimensionless parameter ZT depends on the materials’ transport coefficients: conductivity, thermal conductivity, Seebeck coefficient, and operating temperature. However, due to the coupling between conductivity and thermal conductivity quantified by the Wiedemann-Franz ratio obeyed by standard materials, the quest to increase ZT is a challenge for contemporary materials physics. Novel materials and structures have been proposed to overcome these difficulties on the way to achieve efficient waste heat harvesters with possible applications at large and small scales.

During the lecture, the above main ideas in the theory of thermoelectricity will be discussed, and their application in the nanoscale illustrated by the analysis of the devices consisting of a single or two quantum dots, tunnel coupled to two or more external electrodes. The electrodes may be simple metals, ferromagnets, or superconductors. The steady-state transport characteristics of the devices will be analysed. Special attention will be paid to the role of interactions between the carriers, and the non-linear effects prevalent in such structures.

Keywords: thermoelectricity; heat engines; quantum dots