论文标题
SR $ _2 $ ruo $ _4 $的超导订单参数的对称属性
Symmetry properties of superconducting order parameter in Sr$_2$RuO$_4$
论文作者
论文摘要
在1994年在SR2RUO4（SRO）中发现超导性后不久，人们猜想其顺序参数（OP）的形式与Superfluid He-3中实现的形式相似，即奇数奇特和自旋三重态。在HE-3 A期间实现的手性P波配对受到了几个早期实验的青睐，尤其是MUON的旋转旋转和骑士偏移测量值于1998年发表。但是，2019年初的原始骑士偏移结果被提出了质疑，提出了有关chiral P-Wave，甚至是旋转旋转的旋转型，甚至是旋转式旋转式，还是在Srowike Insros中，是否既有旋转式旋转式”。在这篇简短的教学评论中，我们将通过对抗当前公认的骑士移位结果，两极分化的中子散射（PNS），自旋逆流半量子涡流（HQV）和Josephson实验，并通过标准BCS理论和更多一般性的参数（包括（1）对（1）对中的hamiltonian进行了预测（包括）（1）对中的人（1）（包括1）的对称性（1），并且（1）（包括1）对中的词（1）（1）对中的术语（1）hamiltonian（1） （3）SRO的定性实验特征。我们还为三胞胎状态介绍了一种替代D-Vector的符号，我们认为它非常适合SRO。我们得出的结论是，最新的骑士移位和PNS实验并不排除在SRO的对称组允许的奇数式，自旋 - 三个状态“螺旋”状态，但确实排除了手性P波状态。另一方面，约瑟夫森（Josephson）和HQV实验表明，SRO中的配对不能具有均匀性，旋转式单曲类型，在表面区域或中镜尺寸的样品中，D-ovector必须具有C轴成分，因此显然排除了所有散装P-p-p-p-wave状态，除了chiral p-p-p-p-p-p-p-p-Wave。考虑到Sro的其他重要实验仅在本文中简要介绍了Sro的其他重要实验，讨论了这种相当明显的表面矛盾的可能解决。
Soon after the discovery of superconductivity in Sr2RuO4 (SRO) in 1994, it was conjectured that its order parameter (OP) has a form similar to that realized in the superfluid He-3, namely, odd parity and spin triplet. The chiral p-wave pairing realized in He-3 A-phase was favored by several early experiments, in particular, the muon spin rotation and the Knight shift measurements published in 1998. However, the original Knight shift result was called into question in early 2019, raising the question as to whether the chiral p-wave, or even the spin-triplet pairing itself, is indeed realized in SRO. In this brief pedagogical review, we will address this question by counterposing the currently accepted results of Knight shift, polarized neutron scattering (PNS), spin counterflow half-quantum vortex (HQV), and Josephson experiments with predictions made both by standard BCS theory and by more general arguments based only on (1) the symmetry of the Hamiltonian including the spin-orbital terms, (2) thermodynamics, and (3) the qualitative experimental features of SRO. We also introduce a notation for triplet states alternative to the more popular d-vector one which we believe well suited to SRO. We conclude that the most recent Knight shift and PNS experiments do not exclude in the bulk the odd-parity, spin-triplet "helical" states allowed by the symmetry group of SRO but do exclude the chiral p-wave state. On the other hand, the Josephson and the HQV experiments showed that the pairing in SRO cannot be of the even-parity, spin-singlet type, and in the surface region or in samples of mesoscopic size, the d-vector must have a c-axis component, thus excluding apparently all bulk p-wave states except the chiral p-wave. Possible resolution of this rather glaring prima facie contradiction is discussed, taking into account other important experiments on SRO touched upon only briefly in this article.
