Phase-dependent Andreev molecules and superconducting gap closing in coherently coupled Josephson junctions
Abstract
The Josephson junction (JJ) is an essential element of superconducting (SC) devices for both fundamental and applied physics. The short-range coherent coupling of two adjacent JJs forms the Andreev molecule states (AMSs), which will provide a new ingredient to engineer the SC transport in JJs and control the Andreev qubits. However, no experimental evidence of the AMSs in the coupled JJs has been reported. Here we provide the tunnel spectroscopic results of electrically controllable two planar JJs sharing one SC electrode. We discover that the coupled JJ results are highly modulated from the single JJ results, due to formation of the phase-dependent AMSs, meaning that the two JJs are coherently coupled. In addition, the superconducting gap closing due to the AMS formation is observed. Our results would help in understanding the microscopic mechanism of the coherent coupling and promoting the AMS physics to apply for research of the topological superconductivity and quantum information technology.
Keywords
Cite
@article{arxiv.2303.10540,
title = {Phase-dependent Andreev molecules and superconducting gap closing in coherently coupled Josephson junctions},
author = {Sadashige Matsuo and Takaya Imoto and Tomohiro Yokoyama and Yosuke Sato and Tyler Lindemann and Sergei Gronin and Geoffrey C. Gardner and Sho Nakosai and Yukio Tanaka and Michael J. Manfra and Seigo Tarucha},
journal= {arXiv preprint arXiv:2303.10540},
year = {2023}
}