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Efficiency bounds on thermoelectric transport in magnetic fields: the role of inelastic processes


  Kaoru Yamamoto [1,2]  ,  Ora Entin-Wohlman [2,3]  ,  Amnon Aharony [2,3]  ,  Naomichi Hatano [1,4]  
 [1] Department of Physics, The University of Tokyo
[2] Department of Physics, Ben Gurion University
[3] Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University
[4] Industrial Institute of Science, The University of Tokyo

It has been argued that breaking time-reversal symmetry which can make the Onsager matrix asymmetric is a way to achieve a high thermoelectric efficiency. Benenti et al. recently claimed [1] that in this case one can achieve the Carnot efficiency with a finite power, which appears to contradict the second law of thermodynamics. 

In order to obtain an asymmetric Onsager matrix, we consider an Aharonov-Bohm ring threaded by a magnetic flux, incorporating electron-phonon inelastic scattering [2]. We find that breaking time-reversal symmetry in the presence of the inelastic  process can significantly enhance the figure of merit for delivering electric power by supplying heat from a phonon bath [3]. The efficiency is bounded by the non-negativity of the entropy production of the original three-terminal junction [3].

 

References: 

[1] G. Benenti, K. Saito, and G. Casati, Phys. Rev. Lett. 106, 230602 (2011).

[2] O. Entin-Wohlman and A. Aharony, Phys. Rev. B 85, 085401 (2012).

[3] Kaoru Yamamoto, Ora Entin-Wohlman, Amnon Aharony, and Naomichi Hatano, Phys. Rev. B 94, 121402(R) (2016)