Contrary to the usual assumption, the electron Bloch states in crystals with spin-orbit coupling do not always transform under symmetry operations in the same way as the pure spin-$1/2$ states. This has profound consequences for the symmetry properties and nodal structure of superconductors, especially for the interband gap functions. Focusing on tetragonal superconductors, we show that the interband pairing in the conventional ($s$-wave) channel can have features which are traditionally associated with unconventional pairing, such as triplet components and odd parity, and can produce line nodes in the excitation energy gap. In the $d$-wave case, the interband pairing, which can also be odd in momentum and have a triplet component, changes the positions and topology of the nodal lines.

中文翻译：

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多频带超导体中的异质带间配对

与通常的假设相反，具有自旋轨道耦合的晶体中的电子布洛赫态并不总是以与纯自旋能级相同的方式在对称操作下转变。$\mathrm{1个}/2$状态。这对超导体的对称性和节点结构，特别是对带间隙功能，具有深远的影响。着眼于四边形超导体，我们证明了常规（$s$波通道）可以具有传统上与非常规配对相关的特征，例如三重态分量和奇偶校验，并且可以在激发能隙中产生线节点。在里面$d$在波情况下，带间配对（其动量也可能是奇数并具有三重态分量）会改变节点线的位置和拓扑。