娱乐城

报告题目：Direct Observation of d‑Wave Superconducting Gap Symmetry in Pressurized La3Ni2O7−δ Single Crystals

报告嘉宾：曹紫昱，聊城大学 副教授

报告时间：2026年10月14日 10:00

报告地点：娱乐城 中心校区超硬材料实验楼A区514会议室

主持人：刘广韬

报告摘要

　　The recent discovery of superconductivity in pressure-stabilized bulk La3Ni2O7−δ, with a critical temperature (Tc) exceeding 77 K, has opened a new frontier in high-temperature superconductivity research beyond cuprates1-9. Yet, the superconducting gap structure, including its amplitude and symmetry, the key signatures of a superconducting state, remain elusive due to the overwhelming challenges of gap studies under high pressure10-14. Here, we introduce in situ directional point-contact spectroscopy (PCS) on single crystals under highly hydrostatic pressure, enabling the direct determination of the superconducting gap structure in pressurized La3Ni2O7−δ single crystals. We observe a pronounced anisotropy in the differential conductance: a sharp zero-bias conductance peak (ZBCP) for quasiparticle injection along the [110] direction and V-shaped quasiparticle spectra for injection along the [001] or [100] direction. The strong directional dependence of these spectroscopic features provides evidence for a nodal d-wave pairing symmetry. Measurements of the gap amplitude (Δ) yield a gap-to-Tc ratio of 2Δ/kBTc = 4.2 ± 0.5, positioning La3Ni2O7−δ firmly among unconventional high-Tc superconductors. These findings set stringent constraints on theoretical models for nickelate superconductors and establish a robust spectroscopic approach for understanding superconductors under extreme pressures.

嘉宾简介

　　曹紫昱，男，2013年本科毕业于山东大学，2019年于中国科学技术大学获理学博士学位，曾在德国DESY同步辐射光源、美国阿贡国家重点实验室访问研究。2019年，于韩国成均馆大学开展博士后研究工作，2024年3月加入聊城大学，物理科学与信息工程娱乐城，副教授，山东省“泰山学者”青年专家。主要从事极端条件下基于金刚石对顶砧压机的超导电性研究工作，具有电子强关联体系的研究背景，研究兴趣包括高温超导，电荷密度波，拓扑绝缘体等。近年来，在高水平期刊Nat. commun.、NPG Asia Mater.、J. Phys. Chem. Lett.、Phys. Rev. B等发表论文20余篇。曾主持韩国教育部国家研究基金2.1亿韩元，国自然青年基金，并参与国内外多个科研项目的研究工作。

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娱乐城

物质模拟方法与软件教育部重点实验室