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arXiv · 2006.15329

Excitonic Josephson effect induced by interlayer tunneling current: robust evidence for exciton condensation

Ya-Fen Hsu·Jung-Jung Su
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Abstract

The Josephson effect can be regarded as a striking manifestation of exciton condensation. It has been suggested to tune the condensate phase of bilayer excitons by applying interlayer tunneling current. A poorly-understood phenomenon observed by Huang {\it et al} [Phys. Rev. Lett. $\bf 109$, 156802 (2012)] demonstrates that the critical values of the interlayer tunneling current at either edge can be controlled by passing a second interlayer tunneling current at the other edge. We successfully attribute this novel coupling to excitonic Josephson effect induced by tunneling-current generated relative phases and indicate that Huang's experiment is very robust evidence for exciton condensation. We furthermore make a new proposal: there exists a critical Josephson current beyond which Josephson coupling collapses and external currents prefer to convert into edge-state currents to meet Huang's observation at the second tunneling current above $\pm$16nA -- a sudden decoupling of two edges accompanied by a large interedge voltage. Also, we make a feasible suggestion to detect Josephson current by measuring induced magnetic field of a ring-shaped excitonic Josephson junction. This work not only solves the long-standing uncertainty regarding the identification of exciton condensation but also opens a new direction to explore exciton condensation.

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Ya-Fen Hsu, Jung-Jung Su. 2022-02-05. Excitonic Josephson effect induced by interlayer tunneling current: robust evidence for exciton condensation. https://arxiv.org/abs/2006.15329

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