Speaker: Judy Ji, Massachusetts Institute of Technology (MIT)
Abstract: Nanoscale electrodynamics offers a unique perspective on states with bulk-edge correspondence or spatially dependent excitations. I will first discuss the impact of continuous layer twists on light-matter interaction in three-dimensional transition metal dichalcogenide (TMD) samples measured using electrical probes [1]. Then, I will introduce our latest advancements in optically coupled microwave impedance microscopy, a technique that enhances our capability to explore electrical properties of quantum materials at the nanometer scale. I will discuss our recent studies utilizing this technology to extract spectroscopic information on exciton excitations within TMD systems [2]. Additionally, I will share some of our recent findings on probing the bulk and edge states of topological and correlated electronic states, specifically the fractional Chern insulator states in twisted MoTe2 bilayers [3]. By tuning the carrier density, we observe the system evolving between metallic and FCI states, the latter of which exhibits insulating bulk and conductive edges, as expected from the bulk–boundary correspondence. Further analysis suggests the composite nature of the FCI edge states.
[1] Zhurun Ji, Yuzhou Zhao, Yicong Chen, Ziyan Zhu, Yuhui Wang, Wenjing Liu, Gaurav Modi, Eugene Mele, Song Jin, Ritesh Agarwal, “Opto-twistronic Hall effect in a three-dimensional spiral lattice”, Nature, 634, 69–73 (2024)
[2] Zhurun Ji, Mark E. Barber, Ziyan Zhu, Carlos R. Kometter, Jiachen Yu, Kenji Watanabe, Takashi Taniguchi, Mengkun Liu, Thomas P. Devereaux, Ben Feldman, Zhixun Shen, Local microwave sensing of excitons and their electrical environment, Nature Communications, 16 (1), 9236 (2025)
1. [3] Zhurun Ji*, Heonjoon Park*, Mark E Barber, Chaowei Hu, Kenji Watanabe, Takashi Taniguchi, Jiun-Haw Chu, Xiaodong Xu, Zhi-xun Shen, “Local probe of bulk and edge states in a fractional Chern insulator”, Nature, 635, 578–583 (2024)