Condensed Matter Seminar: Enhanced performance of three-terminal thermoelectric devices

Abstract:

Starting with the work of Bernamont (1937) on resistance uctuations, noisy signals of a vast number of natural processes exhibit 1=f power-spectrum. Such spectra are found in weather data, brain activity, currents of ion-channels and certain chaotic systems to name a few. The wide applicability of this spectrum resulted in conicting theories distributed among many disciplines.

A three-terminal device, comprising two electronic terminals and a thermal one (e.g., a boson bath, Fig. 1), is discussed. In the first part, we investigate the coefficient of performance for the joint operation of cooling one of the electronic terminals and producing electric power. Surprisingly enough, the coefficient of performance can be enhanced as compared to the case where that electronic terminal is cooled by investing thermal power (from the thermal bath) and electric power (from voltage applied across the electronic junction). We next examine the efficiency of an effective two-terminal thermoelectric device under a broken time-reversal symmetry which is derived from the three-terminal thermoelectric device. We find that breaking time-reversal symmetry can enhance the figure of merit for delivering electric power by supplying heat from a phonon bath beyond the one for producing the electric power by investing thermal power from the electronic baths. We also show that such a device cannot reach the Canot efficiency, contrary to a recent claim.

[1] O. Entin-Wohlman and A. Aharony, Three-terminal thermoelectric transport under broken time-reversal symmetry, Phys. Rev. B 85, 085401 (2012).

[2] O. Entin-Wohlman, Y. Imry, and A. Aharony, Enhanced performance of joint cooling and energy production, Phys. Rev. B 91, 054302 (2015).

[3] Kaoru Yamamoto, Ora Entin-Wohlman, Amnon Aharony, and Naomichi Hatano, Efficiency bounds on thermoelectric transport in magnetic fields: the role of inelastic processes, Phys. Rev. B 94, 121402(R) (2016).

Event Organizer: Prof. Eli Eisenberg