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arXiv · 1804.07877

Spontaneous surface current in multi-component cubic superconductors with time-reversal symmetry breaking

Jia-Long Zhang·Wen Huang·Dao-Xin Yao
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Abstract

In this work we present a comprehensive study of the spontaneous currents in time-reversal symmetry breaking (TRSB) multi-component superconductors with cubic crystalline symmetry. We argue, not limiting to cubic lattices, that spontaneous current on certain high-symmetry surfaces can exist only if the TRSB pairing simultaneously breaks a certain pair of mirror symmetries. This is shown to have exact correspondence with the Gingzburg-Landau (GL) theory and is verified by numerical Bogoliubov de-Gennes (BdG) calculations. In the course we extend the BdG to include effects of gap anisotropy and surface disorder, both of which could lead to a much suppressed current. The GL theory has been known to describe well the spontaneous current. However, we highlight a special case where it becomes less adequate, and show that a refined effective theory for low temperatures is needed. These results could shed light on the phenomenology of cubic superconductors such as U$_{1-x}$Th$_x$Be$_{13}$, the filled skutterudites PrOs$_4$Sb$_{12}$, PrPt$_4$Ge$_{12}$ and related compounds.

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Jia-Long Zhang, Wen Huang, Dao-Xin Yao. 2018-07-16. Spontaneous surface current in multi-component cubic superconductors with time-reversal symmetry breaking. https://doi.org/10.1103/physrevb.98.014511

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