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Effects of broken time-reversal symmetry on transmission zeros in the Aharonov-Bohm interferometer

Tae-Suk Kim·Sam Young Cho·Chul Koo Kim·Chang-Mo Ryu
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Abstract

In this paper, we study the behavior of the transmission zeros in the closed Aharonov-Bohm(AB) interferometer with an embedded scattering center in one arm and the corresponding change in the transmission phase when the time-reversal symmetry is broken by magnetic fields. Specifically, we consider three embedded scattering centers: one discrete energy level, a double-barrier well, and a $t$-stub. We find the followings from our model study: (i) The transmission zeros are real when the AB flux is an integer or a half-integer multiple of the flux quantum, and the transmission phase jumps by $π$ at the zeros. (ii) The transmission zeros become complex or are shifted off the real-energy axis when the magnetic AB flux is not an integer or a half-integer multiple of the flux quantum, and the transmission phase evolves continuously. (iii) The distance of the zeros from the real-energy axis or the imaginary part of the transmission zeros is sinusoidal as a function of the magnetic AB phase. We suggest the experimental setup which can test our results.

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Tae-Suk Kim, Sam Young Cho, Chul Koo Kim, Chang-Mo Ryu. 2002-06-12. Effects of broken time-reversal symmetry on transmission zeros in the Aharonov-Bohm interferometer. https://doi.org/10.1103/physrevb.65.245307

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