Direct Evidence of Unconventional Superconductivity in Doped Kagome system RV3Sb5
Abstract
The superconducting pairing symmetry of kagome metals remains a central unresolved question largely because phase-sensitive experiments capable of distinguishing between different possible order parameters have been difficult to implement. The spatial and energetic characteristics of impurity bound states measured by spectroscopic-imaging scanning tunneling microscopy encode information on the superconducting order parameter. Here, we use impurity-bound state spectroscopy to investigate optimally doped RbV3Sb5 where the charge-density wave instability is fully suppressed. We find that the superconducting state is fully gapped and exhibits two distinct energy scales, consistent with a multiband order parameter. Atomic-scale spectroscopy around nonmagnetic defects reveals pronounced particle-hole asymmetric bound states. Comparison with theoretical calculations demonstrates that these bound states are incompatible with conventional s-wave and sign-changing s± pairing. Our calculations also show that the data are fully consistent with a chiral order parameter. Our results establish impurity-bound-state spectroscopy as a powerful phase-sensitive probe of superconductivity in kagome materials and provide strong evidence that optimally doped RbV3Sb5 realizes a fully gapped chiral superconducting state.
Related
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BibTeX
@misc{almoalem2026direct,
title = {{Direct Evidence of Unconventional Superconductivity in Doped Kagome system RV$_3$Sb$_5$}},
author = {Avior Almoalem and Yuqing Xing and Iksu Jang and Daniel J. Schultz and Grgur Palle and Andrea N. Capa Salinas and Stephen D. Wilson and Rafael M. Fernandes and Jörg Schmalian and Vidya Madhavan},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.28848},
eprint = {2608.28848},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.28848},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Direct Evidence of Unconventional Superconductivity in Doped Kagome system RV_3Sb_5
AU - Avior Almoalem
AU - Yuqing Xing
AU - Iksu Jang
AU - Daniel J. Schultz
AU - Grgur Palle
AU - Andrea N. Capa Salinas
AU - Stephen D. Wilson
AU - Rafael M. Fernandes
AU - Jörg Schmalian
AU - Vidya Madhavan
PY - 2026
DA - 2026/08/28
PB - arXiv
DO - 10.48550/arxiv.2608.28848
UR - https://arxiv.org/abs/2608.28848
AB - The superconducting pairing symmetry of kagome metals remains a central unresolved question largely because phase-sensitive experiments capable of distinguishing between different possible order parameters have been difficult to implement. The spatial and energetic characteristics of impurity bound states measured by spectroscopic-imaging scanning tunneling microscopy encode information on the superconducting order parameter. Here, we use impurity-bound state spectroscopy to investigate optimally doped RbV_3Sb_5 where the charge-density wave instability is fully suppressed. We find that the superconducting state is fully gapped and exhibits two distinct energy scales, consistent with a multiband order parameter. Atomic-scale spectroscopy around nonmagnetic defects reveals pronounced particle-hole asymmetric bound states. Comparison with theoretical calculations demonstrates that these bound states are incompatible with conventional s-wave and sign-changing s^± pairing. Our calculations also show that the data are fully consistent with a chiral order parameter. Our results establish impurity-bound-state spectroscopy as a powerful phase-sensitive probe of superconductivity in kagome materials and provide strong evidence that optimally doped RbV_3Sb_5 realizes a fully gapped chiral superconducting state.
ER -