超净URu $_2$ Si $_2$中低临界场的反常温度依赖性
Anomalous Temperature Dependence of Lower Critical Field in Ultraclean URu$_2$Si$_2$
摘要：
为了研究隐藏有序态中的URu_2Si_2的神秘超导态，我们精确地测定了H的下临界场H_{c1}，下临界场为55 mK|| a和H|| C.为此，在剩余电阻率比超过700的超净单晶（T_c = 1.4K）上测量了局部磁感应强度的位置关系。我们发现，H_{c1}的温度依赖性显着不同于任何其他超导体。H的整个H_{c1}（T）||用最近的热导率和比热测量结果提出的具有线节点和点节点的两种超导能隙结构很好地解释了A。对于H|| c，观察到H_{c1}（T）中具有明显扭结的斜率变化，这不能由两个间隙来解释。这种行为对于H|| c与在UPt_3和U_{1-x} Th_ xBe_{13}中发现的与转变到另一超导相有关的H_{c1}（T）的尖点行为形成鲜明对比。所观察到的异常低场抗磁响应可能与由于多组分超导序参量与时间反演对称性破缺而导致的与手征畴相关的奇特涡旋动力学有关。
英文摘要：
To investigate a mysterious superconducting state of URu_2Si_2 embedded in the so-called hidden order state, the lower critical field H_{c1} is precisely determined down to 55 mK for H || a and H || c. For this purpose, the positional dependence of the local magnetic induction is measured on ultraclean single crystals (T_c = 1.4 K) with residual resistivity ratio exceeding 700. We find that the temperature dependence of H_{c1} significantly differs from that of any other superconductors. The whole H_{c1}(T) for H || a are well explained by the two superconducting gap structures with line and point nodes, which have been suggested by the recent thermal conductivity and specific heat measurements. On the other hand, for H || c, a change of slope with a distinct kink in H_{c1}(T), which cannot be accounted for by two gaps, is observed. This behavior for H || c sharply contrasts with the cusp behavior of H_{c1}(T) associated with a transition into another superconducting phase found in UPt_3 and U_{1-x}Th_xBe_{13}. The observed anomalous low-field diamagnetic response is possibly related to a peculiar vortex dynamics associated with chiral domains due to the multicomponent superconducting order parameter with broken time reversal symmetry.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
