Observation of a Ubiquitous(π,π)-Type Nematic Superconducting Order in the Whole Superconducting Dome of Ultra-Thin BaFe2-xNixAs2 Single Crystals

• 作者: Yu Dong Yangyang Lv Zuyu Xu M.Abdel-Hafiez A.N.Vasiliev Haipeng Zhu Junfeng Wang Liang Li Wanghao Tian Wei Chen Song Bao Jinghui Wang Yueshen Wu Yulong Huang Shiliang Li Jie Yuan Kui Jin Labao Zhang Huabing Wang Shun-Li Yu Jinsheng Wen Jian-Xin Li Jun Li Peiheng Wu
• 来源期刊: 中国物理快报（英文版）
• 年，卷（期）: 2021,（9）
• 所属期刊栏目: CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL,MAGNETIC, AND OPTICAL PROPERTIES
• 页码范围: 116-126
• 页数: 11页
• 语种: 英文
• DOI: 10.1088/0256-307X/38/9/097401

摘要

In iron-based superconductors,the(0,π)or(π,0)nematicity,which describes an electronic anisotropy with a four-fold symmetry breaking,is well established and believed to be important for understanding the superconducting mechanism.However,how exactly such a nematic order observed in the normal state can be related to the superconducting pairing is still elusive.Here,by performing angular-dependent in-plane magnetoresistivity using ultra-thin flakes in the steep superconducting transition region,we unveil a nematic superconducting order along the(π,π)direction in electron-doped BaFe2-xNixAs2 from under-doped to heavily overdoped regimes with x=0.065-0.18.It shows superconducting gap maxima along the(π,π)direction rotated by 45° from the nematicity along(0,π)or(π,0)direction observed in the normal state.A similar(π,π)-type nematicity is also observed in the under-doped and optimally doped hole-type Ba1-yKyFe2As2,with y=0.2-0.5.These results suggest that the(π,π)nematic superconducting order is a universal feature that needs to be taken into account in the superconducting pairing mechanism in iron-based superconductors.