论文标题
微观的金茨堡 - landau理论和单人订单，$ _2 $ ruo $ _4 $
A microscopic Ginzburg--Landau theory and singlet ordering in Sr$_2$RuO$_4$
论文作者
论文摘要
在最近的核磁共振（NMR）骑士换档实验中，确定SR $ _2 $ _4 $ _4 $（SRO）SR $ _4 $ _4 $（SRO）的超导顺序的长期追求已引起人们对超导状态下自旋三型配对的可能性的怀疑。作为推定的解决方案，已经提出了由偶然的接近阶层引起的$ d+ig $ - 波订单参数，包括$ d+ig $ - 波订单参数[S. S. A. Kivelson等人，NPJ量子材料$ \ bf {5} $，43（2020）]。在这里，我们开发了一个通用的金茨堡 - 多型超导体理论。我们将理论应用于SRO并预测顺序参数成分的相对大小。在第二阶参数组件开始时，预期的热容量跳跃被发现超过了由于缺乏第二跳而推断出的当前阈值。我们的结果严格限制了$ d+ig $订单的理论，以及其他候选者在SRO中造成的其他候选者。我们讨论问题的可能解决方案。
The long-standing quest to determine the superconducting order of Sr$_2$RuO$_4$ (SRO) has received renewed attention after recent nuclear magnetic resonance (NMR) Knight shift experiments have cast doubt on the possibility of spin-triplet pairing in the superconducting state. As a putative solution, encompassing a body of experiments conducted over the years, a $d+ig$-wave order parameter caused by an accidental near-degeneracy has been suggested [S. A. Kivelson et al., npj Quantum Materials $\bf{5}$, 43 (2020)]. Here we develop a general Ginzburg--Landau theory for multiband superconductors. We apply the theory to SRO and predict the relative size of the order parameter components. The heat capacity jump expected at the onset of the second order parameter component is found to be above the current threshold deduced by the experimental absence of a second jump. Our results tightly restrict theories of $d+ig$ order, and other candidates caused by a near-degeneracy, in SRO. We discuss possible solutions to the problem.
