Seminar: Exploring the interplay between charge orders and unconventional superconductivity

彭莹莹

北京大学量子材料科学中心

报告时间：2023年12月4日（周一）下午15:30

报告地点：紫金港校区海纳苑8幢319室

摘要：

The investigation of unconventional superconductivity (SC) represents a paramount challenge in condensed matter physics, with the intricate relationship between SC and other ordered states, such as charge order, remaining a focal point. This connection is notably evident across diverse materials, emphasizing the need to unravel the underlying mechanisms. X-ray diffraction (XRD) is a direct and formidable technique for elucidating crystal structure and long-range order in materials. Furthermore, resonant X-ray scattering enhances investigative prowess by offering elemental specificity and the ability to probe electronic states.

In this presentation, I will showcase our advanced X-ray studies focused on charge orders in two distinct classes of materials: high-Tc cuprate superconductors and Kagome superconductors. Our findings encompass three key revelations: (i) the emergence of high-temperature superconductivity from the charge order insulating phase proximate to the insulating regime [1]; (ii) the identification of a charge order in the extremely overdoped La2−xSrxCuO4, extending beyond the superconducting dome [2]; and (iii) the disclosure of coexisting and competing charge density wave (CDW) phases in CsV3Sb5, providing novel insights into the intricacies of Kagome superconductors [3,4]. Through these studies, we contribute to the evolving understanding of the interplay between superconductivity and charge fluctuations, shedding light on the origins of unconventional superconductivity in these fascinating materials.

References 

1. Changwei Zou et al., under review.

2. Qizhi Li et al., Physical Review Letters 131, 116002 (2023) (Editors’ Suggestion)

3. Qian Xiao et al., Physical Review Materials 7, 074801 (2023).

4. Qian Xiao et al., Physical Review Research 5, L012032 (2023).

报告人简介：

Yingying Peng is an assistant professor at the International Center for Quantum Materials, Peking University. She received her BS from Wuhan University in 2008 and PhD from the Institute of Physics, Chinese Academy of Sciences in 2013. Then she worked as a postdoc at the Polytechnic University of Milan (Italy) from 2013 to 2017 and at the University of Illinois at Urbana-Champaign (USA) from 2018 to 2019. Her research interests include studying the elementary excitations of correlated materials and the mechanism of unconventional superconductivity using advanced X-ray scattering methods. She has published more than 60 papers, including Science, Nature journals, Physical Review Letter, etc, with citations more than 4500 times.