The thermoelectric effect is a phenomenon in which a temperature difference applied to a conducting material induces a voltage difference. This effect has a range of important applications, since it allows one to convert waste heat into useful electric power. In conventional metals and semiconductors, however, the strength of the thermoelectric effect faces fundamental limitations. In this talk I consider whether these same limitations apply to the three-dimensional nodal semimetals. I show that, surprisingly, the electron-hole symmetry of nodal semimetals allows for a thermopower that grows without bound under the application of a strong magnetic field. This nonsaturating thermopower can be understood in terms of quantum Hall-like edge states, and the corresponding thermoelectric conductivity achieves a universal, quantized value at large magnetic field. These effects can be readily observed experimentally, and they may enable the development of thermoelectric devices with record efficiency.
Brian Skinner / MIT
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