Distinguishing between s + id and s + is pairing symmetries in multiband superconductors through spontaneous magnetization pattern induced by a defect
Distinguishing between s + id and s + is pairing symmetries in multiband superconductors through spontaneous magnetization pattern induced by a defect
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s id 和 s 之间的区别是多带超导体中通过缺陷引起的自发磁化模式配对对称性
DOI：
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发表时间：
2016
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影响因子：
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通讯作者：
A. Chubukov
中科院分区：
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作者：
Shizeng Lin;S. Maiti;A. Chubukov
铁离子超导体$mathrm{Ba_{1-x}K_xFe_2As_2}$中对态的对称性仍然存在争议。在最佳掺杂（$x约0.4$）下，很可能是$s$-波，但对于$x=1$，对于$s$-波和$d$-波都有实验和理论上的争论。根据$x=1$的选择，中间体$s+is$和$s+id$被提出用于中间掺杂$ 0.4 < x < 1$。在这两种状态下，时间反转对称性被打破，允许自发磁化。本文利用摄动理论和金兹堡-朗道自由能泛函的数值计算，研究了$s+is$和$s+id$态中由非磁性缺陷引起的自发磁化。我们发现在这两种状态下，由于序参量对称性的不同，磁化强度的角依赖性是不同的。我们的结果表明了一种可能的方法来区分多波段超导体中$s+is$和$s+id$对对称性。
The symmetry of the pairing state in iron pnictide superconductor $mathrm{Ba_{1-x}K_xFe_2As_2}$ is still controversial. At optimal doping ($x approx 0.4$), it is very likely $s$-wave, but for $x=1$ there are experimental and theoretical arguments for both $s$-wave and $d$-wave. Depending on the choice for $x=1$, intermediate $s+is$ and $s+id$ states have been proposed for intermediate doping $ 0.4 < x < 1$. In both states, the time reversal symmetry is broken and a spontaneous magnetization is allowed. In this work we study a spontaneous magnetization induced by a nonmagnetic defect in the $s+is$ and $s+id$ states by using a perturbation theory and numerical calculations for the Ginzburg-Landau free energy functional. We show that the angular dependence of the magnetization is distinct in these two states due to the difference in symmetry properties of the order parameters. Our results indicate a possible way to distinguish between the $s+is$ and $s+id$ pairing symmetries in multi-band superconductors.