Deciphering Chiral Superconductivity via Impurity Bound States

Yuchang Cai; Rui-Xing Zhang

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arXiv · 2506.20842

Deciphering Chiral Superconductivity via Impurity Bound States

Yuchang Cai·Rui-Xing Zhang

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Abstract

Determining the symmetry of Cooper pairs remains a central challenge in the study of unconventional superconductors, particularly for chiral states that spontaneously break time-reversal symmetry. Here we demonstrate that point-like impurities in chiral superconductors generate in-gap bound states with a distinctive asymmetry: the local density of states at the impurity site vanishes at one bound-state energy, but not at its particle-hole conjugate. We prove this behavior analytically in generic two-dimensional, single-band chiral superconductors, showing it arises from a fundamental interplay between pairing chirality and crystalline rotation symmetry. Our numerical simulations confirm that this diagnostic feature persists in multiband systems and for spatially extended impurities. Our results establish a symmetry-enforced real-space diagnostic for chiral superconductivity at the atomic scale.

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Yuchang Cai, Rui-Xing Zhang. 2025-06-25. Deciphering Chiral Superconductivity via Impurity Bound States. https://arxiv.org/abs/2506.20842

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