Observation of Fermi-surface-dependent anisotropic Cooper pairing in kagome superconductor CsV₃Sb₅

TY - JOUR

T1 - Observation of Fermi-surface-dependent anisotropic Cooper pairing in kagome superconductor CsV3Sb5

AU - Mine, Akifumi

AU - Zhong, Yigui

AU - Liu, Jinjin

AU - Suzuki, Takeshi

AU - Najafzadeh, Sahand

AU - Uchiyama, Takumi

AU - Yin, Jia Xin

AU - Wu, Xianxin

AU - Shi, Xun

AU - Wang, Zhiwei

AU - Yao, Yugui

AU - Okazaki, Kozo

N1 - Publisher Copyright: © The Author(s) 2025.

PY - 2025/12

Y1 - 2025/12

N2 - In the recently discovered kagome superconductor AV3Sb5 (A = K, Rb, and Cs), superconductivity is intertwined with an unconventional charge density wave order. The pairing symmetry remains elusive owing to the lack of direct measurement of the superconducting gap in the momentum space. Here, utilizing laser-based ultra-high-resolution and low-temperature angle-resolved photoemission spectroscopy, we observe Fermi-surface-dependent anisotropic Cooper pairing in kagome superconductor CsV3Sb5. We detect a highly anisotropic superconducting gap structure with anisotropy exceeding 80% and a gap maximum along the V-V bond direction on a Fermi surface originating from the 3d-orbital electrons of the V kagome lattice. This is in stark contrast to the isotropic superconducting gap structure on the Fermi surface occupied by Sb 5p-orbital electrons. Our direct observation of the Fermi-surface-dependent anisotropic pairing in CsV3Sb5 is fundamental for understanding the intertwined orders in the ground state of kagome superconductors.

AB - In the recently discovered kagome superconductor AV3Sb5 (A = K, Rb, and Cs), superconductivity is intertwined with an unconventional charge density wave order. The pairing symmetry remains elusive owing to the lack of direct measurement of the superconducting gap in the momentum space. Here, utilizing laser-based ultra-high-resolution and low-temperature angle-resolved photoemission spectroscopy, we observe Fermi-surface-dependent anisotropic Cooper pairing in kagome superconductor CsV3Sb5. We detect a highly anisotropic superconducting gap structure with anisotropy exceeding 80% and a gap maximum along the V-V bond direction on a Fermi surface originating from the 3d-orbital electrons of the V kagome lattice. This is in stark contrast to the isotropic superconducting gap structure on the Fermi surface occupied by Sb 5p-orbital electrons. Our direct observation of the Fermi-surface-dependent anisotropic pairing in CsV3Sb5 is fundamental for understanding the intertwined orders in the ground state of kagome superconductors.

UR - https://www.scopus.com/pages/publications/105023398145

U2 - 10.1038/s43246-025-01002-y

DO - 10.1038/s43246-025-01002-y

M3 - Article

AN - SCOPUS:105023398145

SN - 2662-4443

VL - 6

JO - Communications Materials

JF - Communications Materials

IS - 1

M1 - 276

ER -