In a two-dimensional system, Rashba spin-orbit coupling can lift spin degeneracy and give the opposite spin chirality to two split Fermi circles from two Rashba bands. Here, we propose a generic model that can produce unconventional Rashba bands. In such cases, the two Fermi circles from the two bands exhibit the same spin chirality. When various interactions are taken into account, many unique physics can emerge in systems with unconventional Rashba bands compared to those with conventional Rashba bands. For instance, we study the spin galvanic effect by considering two cases: one with potential impurity scattering and the other with magnetic impurity scattering. In both cases, we find that the efficiency of the spin galvanic effect is strongly enhanced in unconventional Rashba bands compared to conventional Rashba bands. More intriguingly, we find that the efficiency of conventional Rashba bands is insensitive to either potential or magnetic impurity scattering. However, the efficiency of unconventional Rashba bands can be further enhanced by magnetic impurity scattering compared to the potential impurity scattering. Thus, unconventional Rashba bands can produce giant spin galvanic effect. These results demonstrate that this model is useful for exploring abnormal physics in systems with unconventional Rashba bands.

中文翻译：

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具有非常规 Rashba 能带和巨大自旋电偶效应的通用模型

在二维系统中，Rashba 自旋轨道耦合可以提升自旋简并性，并为来自两个 Rashba 能带的两个分裂费米圆提供相反的自旋手性。在这里，我们提出了一个可以产生非常规 Rashba 乐队的通用模型。在这种情况下，两个能带的两个费米圆表现出相同的自旋手性。当考虑到各种相互作用时，与具有传统 Rashba 能带的系统相比，具有非常规 Rashba 能带的系统中可以出现许多独特的物理现象。例如，我们通过考虑两种情况来研究自旋电偶效应：一种具有潜在的杂质散射，另一种具有磁性杂质散射。在这两种情况下，我们发现与传统的 Rashba 能带相比，非常规 Rashba 能带的自旋电偶效应的效率大大增强。更有趣的是，我们发现传统 Rashba 能带的效率对势或磁杂质散射不敏感。然而，与潜在杂质散射相比，非常规 Rashba 能带的效率可以通过磁杂质散射进一步提高。因此，非常规的拉什巴能带可以产生巨大的自旋电偶效应。这些结果表明，该模型对于探索具有非常规 Rashba 能带的系统中的异常物理现象非常有用。