发表机构
Institute for Theory of Condensed Matter, Karlsruhe Institute of Technology; Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology（卡尔斯鲁厄理工学院凝聚态理论研究所; 卡尔斯鲁厄理工学院量子材料与技术研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
我们提出应变通过混合s波与双分量配对通道并增强Lifshitz耦合，在无磁场下诱导螺旋超导态，产生非单调的二极管效应，且方向可随主应变反转或剪切应变连续旋转。
AI 中文摘要
受PbTaSe$_2$中观察到的应变诱导零场超导二极管效应的启发，我们确定了一种机制，通过该机制，应变无需磁性或外部磁场即可产生非互易超导输运。单轴应变将主导的$s$波序参量与次主导的双分量配对通道混合，并增强它们对称性允许的Lifshitz耦合。超过临界应变时，该耦合驱动系统转变为螺旋态，该态具有自发选择的有限库珀对动量和破缺的时间反演对称性。由此产生的二极管效应在应变下通常是非单调的，并且对平行和垂直于残余镜面的电流表现出不同的响应，与实验一致。我们的理论预测，反转主应变会使二极管方向切换$90^\circ$，而剪切应变则使其连续旋转。这些结果确立了应变作为一种对称性选择的手段，用于创建、控制和诊断自发螺旋超导性。
英文摘要
Motivated by the strain-induced zero-field superconducting diode effect observed in PbTaSe$_2$, we identify a mechanism by which strain generates nonreciprocal superconducting transport without magnetism or an external magnetic field. Uniaxial strain mixes a dominant $s$-wave order parameter with a subdominant two-component pairing channel and enhances their symmetry-allowed Lifshitz coupling. Beyond a critical strain, this coupling drives a transition into a helical state with spontaneously selected finite Cooper-pair momentum and broken time-reversal symmetry. The resulting diode effect is generically non-monotonic in strain and exhibits distinct responses for currents parallel and perpendicular to the residual mirror plane, consistent with experiment. Our theory predicts that reversing the principal strain switches the diode direction by $90^\circ$, while shear strain rotates it continuously. These results establish strain as a symmetry-selective means of creating, controlling, and diagnosing spontaneous helical superconductivity.
Comments5 pages, 3 figures
