We consider a Josephson bijunction consisting of a thin $SIS\pi$-Josephson junction sandwiched between two-dimensional semiconducting layers with strong Rashba spin-orbit interaction. Each of these layers forms an $SNS$ junction due to proximity-induced superconductivity. The $SIS$ junction is assumed to be thin enough such that the two Rashba layers are tunnel coupled. We show that, by tuning external gates, this system can be controllably brought into a time-reversal invariant topological superconducting phase with a Kramers pair of Majorana bound states being localized at the end of the normal region for a large parameter phase space. In particular, in the strong spin-orbit interaction limit, the topological phase can be accessed already in the regime of small tunneling amplitudes.

中文翻译：

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平面约瑟夫森双结中的时间逆不变拓扑超导

我们考虑由薄 $\mathrm{小号}\mathrm{一世}\mathrm{小号}\pi$-Josephson结夹在具有强Rashba自旋轨道相互作用的二维半导体层之间。这些层中的每一个都形成一个$\mathrm{小号}ñ\mathrm{小号}$由于邻近感应超导而导致的结。的$\mathrm{小号}\mathrm{一世}\mathrm{小号}$假设结足够薄，以使两个Rashba层隧道耦合。我们表明，通过调整外部门，可以将系统可控地转变为时间逆不变拓扑超导相，其中Kramers对的马约拉纳结合态位于大参数相空间的正常区域的末端。特别地，在强的自旋轨道相互作用极限中，已经可以在小的隧穿振幅的情况下进入拓扑阶段。