第2回物理工学科教室談話会[Dr. Danfeng Li・6/7(水)15時～]

講　師：Dr. Danfeng Li
所　属：Assistant Professor, Department of Physics, City University of Hong Kong
題　目：‘Unconventional’ Superconductivity in Infinite-Layer Nickelates
日　時:：2023 年 6 月 7 日(水) 15:00～
Date and Time：June 7, 2023 (Wednesday) 15:00-
場　所：工 6 号館 1 階大会議室 (ハイブリッド開催)
Place：Large Conference room, 1st floor, Engineering Bldg. 6 (Hybrid)
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Abstract:
Developing new techniques to design and discover novel superconductors, especially those with unusual symmetries of superconducting order parameters and/or exotic pairing mechanisms, opens new doors to future applications in quantum devices. The recent discovery of superconductivity in infinite-layer nickelates has engendered reviving interest in the study of a cuprate-analog system [1]. Notably, superconducting nickelates display signatures of intriguing similarities and distinctions to the cuprates in their phase diagrams, proximity to strongly correlated electronic phases [2], antiferromagnetic interactions [3], superconducting anisotropy [4], etc. Partially owing to the non-trivial challenges in materials synthesis and their thin-film nature, experimental demonstration of the intrinsic properties of this materials family has still been limited [5,6]. In this talk, I will introduce this new family of superconductors synthesized by a soft-chemistry approach and highlight the key aspects of their electronic and magnetic structure. I will also present our latest developments in synthetic approaches to the materials system and probing of their distinct features, in a broader context of the unusual role that rare-earth elements and chemical environment play. Finally, I will suggest how new applications of kinetic-based synthetic approaches in oxide heterostructures provide a broad opportunity to create novel quantum systems in previously inaccessible ways.

Reference:
[1] D. Li et al., Nature 572, 624 (2019).
[2] D. Li et al., Physical Review Letters 125, 27001 (2020).
[3] H. Lu et al., Science 373, 213 (2021).
[4] B. Y. Wang et al., Nature Physics 17, 473 (2021).
[5] K. Lee et al., APL Materials 8, 041107 (2020).
[6] K. Lee et al., arXiv:2203.02580 (2022).

Biography:
Dr Danfeng Li is currently an Assistant Professor of Physics at City University of Hong Kong. Dr Li obtained his B.Eng. from Zhejiang University and M.Phil. from The Hong Kong Polytechnic University (advisor: Prof Ji-yan Dai). Shortly after earning his Ph.D. (2016) in the Department of Quantum Matter Physics at University of Geneva (advisor: Prof Jean-Marc Triscone), Dr Li joined Stanford University as a Swiss National Science Foundation postdoctoral fellow, working with Prof Harold Hwang. He started working at CityU from November 2020. Dr Li’s main research interests span across condensed-matter physics and materials science, focusing on atomic-scale fabrication of oxide heterostructures and nanomembranes, kinetic based synthesis of unconventional quantum materials, low-dimensional superconductivity, oxide interfaces for emergent states, etc. In 2019, a team led by Dr Li and Prof Hwang discovered the first nickelate superconductor, which had been a target of continuous materials search for over three decades. For his discovery, Dr Li was named to the list of 2021 MIT Technology Review 35 Innovators under 35 (China).

紹介教員: 岩佐 義宏教授（物理工学専攻）、Max Hirschberger准教授（物理工学専攻）