伽玛大讲堂（第19期）： Discovery of high-Tc superconductivity
Discovery of high-Tc superconductivity in a nickelate under pressure
报告人介绍：
王猛，中山大学物理学院教授、博士生导师，现任中山大学物理学院副院长、广东省磁电物性分析与器件重点实验室副主任、物理学院中子科学与技术中心主任。本科毕业于吉林大学物理学院，博士毕业于中国科学院物理研究所，曾在加州大学伯克利分校开展博士后研究工作。王猛教授已发表论文70余篇，包括Nature、Nature Physics、Nature Communications、Physical Review Letters、Physical Review B等杂志，是Science China-PMA杂志青年编委，长期担任Nature、Nature Physics、Physical Review Letters等杂志审稿人。王猛教授研究兴趣包括非常规超导材料和量子磁性材料的物性及机理研究，研究方法包括材料生长、中子散射、高压技术等，参与中国首台高能非弹性中子散射飞行时间谱仪建设，代表性研究工作包括发现新的镍氧化物高温超导体等。
报告摘要：
High-transition-temperature (high-Tc) superconductivity in cuprates has been discovered for more than three decades, but the underlying mechanism remains a mystery. Cuprates are the only unconventional superconducting family that host bulk superconductivity with Tcs above the liquid nitrogen boiling temperature at 77 Kelvin. We found superconductivity in single crystals of La3Ni2O7 grown by the high-pressure floating zone method with a maximum Tc of 80 K at pressures between 14.0-43.5 gigapascals. Our collaborators have confirmed the high Tc superconductivity on our samples independently. The superconducting phase under high pressure exhibits an orthorhombic structure of Fmmm space group with the 3dx2-y2 and 3dz2 orbitals of Ni cations strongly mixing with oxygen 2p orbitals. Density functional theory calculations suggest the superconductivity emerges coincidently with the metallization of the σ-bonding bands under the Fermi level, consisting of the 3dz2 orbitals with the apical oxygens connecting Ni-O bilayers. Thus, the discoveries not only reveal important clues for the high-Tc superconductivity in this Ruddlesden-Popper double-layered perovskite nickelates but also provide a new family of compounds to investigate the high-Tc superconductivity mechanism.
