American Physical Society (APS) Acta Medica Okayama 0031-9007 137 9 2026 Strain-Tuned Nodal Superconductivity in the Charge-Ordered Kagome Metal CsV3⁢Sb5 096003 EN Yusuke Takeuchi Department of Physics, Okayama University Akito Kobayashi Department of Physics, Okayama University Saki Uchida Department of Physics, Okayama University Takumi Nagao Department of Physics, Okayama University Seigo Ogawa Department of Physics, Okayama University Rui Zhou Institute of Physics, Chinese Academy of Sciences, and Beijing National Laboratory for Condensed Matter Physics Shinji Kawasaki Department of Physics, Okayama University Fei Song Fujian Provincial Collaborative Innovation Center for Advanced High-Field Superconducting Materials and Engineering, College of Physics and Energy, Fujian Normal University Hao Ni Fujian Provincial Collaborative Innovation Center for Advanced High-Field Superconducting Materials and Engineering, College of Physics and Energy, Fujian Normal University Yong Zhao Fujian Provincial Collaborative Innovation Center for Advanced High-Field Superconducting Materials and Engineering, College of Physics and Energy, Fujian Normal University Guo-qing Zheng Department of Physics, Okayama University The nature of the superconducting pairing symmetry in the kagome metal CsV3⁢Sb5 and its relationship with the charge density wave (CDW) order are central unresolved issues. Here, we investigate the evolution of superconductivity in CsV3⁢Sb5 under in situ uniaxial pressure using 121Sb nuclear quadrupole resonance (NQR). We find that tensile strain significantly enhances the superconducting transition temperature, 𝑇c, while the CDW remains unchanged, demonstrating that superconductivity can be tuned independently of the bulk charge order. At a tensile strain of 𝜖 =+0.90%, the nuclear spin-lattice relaxation rate reveals a remarkable double transition: an upper transition at 𝑇c⁢1=3.6  K to a nodal gap state, and a lower one at 𝑇c⁢2=3.0  K characterized by a nodeless gap. These results evidence degenerate superconducting states with different gap symmetry in the kagome metal at ambient pressure which split under strain. Our Letter demonstrates a high tunability of superconductivity by uniaxial pressure. No potential conflict of interest relevant to this article was reported.

Nature Portfolio Acta Medica Okayama 2041-1723 15 1 2024 Strain-induced long-range charge-density wave order in the optimally doped Bi2Sr2-x Lax CuO6 superconductor 5082 EN Shinji Kawasaki Department of Physics, Okayama University Nao Tsukuda Department of Physics, Okayama University Chengtian Lin Max-Planck-Institut fur Festkorperforschung Guo-Qing Zheng Department of Physics, Okayama University The mechanism of high-temperature superconductivity in copper oxides (cuprate) remains elusive, with the pseudogap phase considered a potential factor. Recent attention has focused on a long-range symmetry-broken charge-density wave (CDW) order in the underdoped regime, induced by strong magnetic fields. Here by Cu-63,Cu-65-nuclear magnetic resonance, we report the discovery of a long-range CDW order in the optimally doped Bi2Sr2-xLaxCuO6 superconductor, induced by in-plane strain exceeding divided by epsilon divided by = 0.15 %, which deliberately breaks the crystal symmetry of the CuO2 plane. We find that compressive/tensile strains reduce superconductivity but enhance CDW, leaving superconductivity to coexist with CDW. The findings show that a long-range CDW order is an underlying hidden order in the pseudogap state, not limited to the underdoped regime, becoming apparent under strain. Our result sheds light on the intertwining of various orders in the cuprates. No potential conflict of interest relevant to this article was reported.