报告摘要：

　　Moiré crystals support flat bands with significant electron correlation effects, providing a novel platform for realizing unconventional superconductivity. In this talk, I will discuss our recent theoretical work on unconventional superconducting phenomena in moiré crystals. In the first part of the talk, I will present our study of unconventional Josephson effects mediated by valley-polarized states in MATBG Josephson junctions. We show that valley polarization, combined with trigonal warping effects, can lead to φ₀-Josephson effects and Josephson diode behavior, even in the absence of spin-orbit coupling. I will also introduce our recent proposal for realizing Majorana fermions using Josephson junctions in low-dimensional materials. Finally, I will discuss the orbital FFLO pairing state in moiré homobilayer transition metal dichalcogenides.

References:

[1]Ying-Ming Xie, Dmitri K Efetov, K. T. Law, Physical Review Research 5, 023029 (2023).

[2] Ying-Ming Xie, ´Etienne Lantagne-Hurtubise, Andrea F. Young, Stevan Nadj-Perge, and

Jason Alicea, Phys. Rev. Lett. 131, 146601 (2023)

[3] Ying-Ming Xie, K. T. Law, Orbital Fulde-Ferrell pairing state in moir´e Ising superconductors, Phys. Rev. Lett. 131, 016001 (2023)

报告人简介：

　　Dr. Xie obtained a Bachelor’s degree in Physics from Beijing Normal University in 2016. Then he joined Prof. K. T. Law’s group at HKUST and obtained a PhD in Physics in 2021. After PhD graduation, he became a Hong Kong RGC Postdoc Fellow and stayed at HKUST until 2023and then moved to the RIKEN Center for Emergent Matter Science (CEMS) as a Special Postdoctoral Researcher and have been working with Prof. Naoto Nagaosa since then.  His main research directions are topological superconductors, correlated states and unconventional superconductivity in 2D materials, quantum geometry related transport and optical responses.