标题： 双量子点器件中的超导二极管效应 显示英文标题

标题： Superconducting Diode Effect in Double Quantum Dot Device

摘要： 超导二极管效应（SDE）在耦合到三个超导电极的双量子点中被理论研究，$L$，$R1$和$R2$。 电极 $L$通常连接到两个量子点（QD1，QD2），而电极 $R1$（$R2$）仅连接到 QD1（QD2）。 相位差$\varphi_{1}$在导联$L$和$R1$之间以及相位差$\varphi_{2}$在导联$L$和$R2$之间是独立调节的。 铅中的临界电流$R1$的方向依赖性取决于其方向，除非$\varphi_{2} = 0$，$\pi$，这可归因于量子点之间的安德烈夫分子的形成。 在没有电子-电子相互作用$U$的情况下，当量子点中的能级调谐到铅中的费米能级时，安德烈夫束缚态的谱在$\varphi_{1}-\varphi_{2}$平面内形成狄拉克锥。 当$\varphi_{2}$设置为狄拉克点的值时，SDE 增强到几乎 30%。 在存在$U$的情况下，当$U$小于电极中的超导能隙时，仍然观察到 SDE。 我们的器件应该是 SDE 的最小模型之一，因为具有单个 QD 的类似器件不显示 SDE。 显示英文摘要

摘要： Superconducting diode effect (SDE) is theoretically examined in double quantum dot coupled to three superconducting leads, $L$, $R1$ and $R2$. Lead $L$ is commonly connected to two quantum dots (QD1, QD2) while lead $R1$ ($R2$) is connected to QD1 (QD2) only. The phase differences $\varphi_{1}$ between leads $L$ and $R1$ and $\varphi_{2}$ between leads $L$ and $R2$ are tuned independently. The critical current into lead $R1$ depends on its direction unless $\varphi_{2} = 0$, $\pi$, which is ascribable to the formation of Andreev molecule between the QDs. In the absence of electron-electron interaction $U$ in the QDs, the spectrum of the Andreev bound states forms Dirac cones in the $\varphi_{1}-\varphi_{2}$ plane if the energy levels in the QDs are tuned to the Fermi level in the leads. The SDE is enhanced to almost 30\% when $\varphi_{2}$ is set to the value at the Dirac points. In the presence of $U$, the SDE is still observed when $U$ is smaller than the superconducting energy gap in the leads. Our device should be one of the minimal models for the SDE since a similar device with a single QD does not show the SDE.