报告题目：Imaging and Harnessing the Topological Boundary Modes
报告时间：2026年7月2日（周四）15:30
报告地点：鼓楼校区唐仲英楼 B501
报 告 人：Prof. Zhenyu Wang（University of Science and Technology of China）
摘 要：Topologically protected edge channels show prospects for quantum devices [1]. In this talk we provide evidence for robust topological helical edge states within a novel topology named three-dimensional (3D) QSHIs. Its topology originates solely from a nonzero spin Chern number for each plane of the crystal and is realized in both bulk α-Bi4I4 with trivial symmetry indicators and α-Bi4Br4 with inversion Z4 index. We experimentally observe the edge modes at each type of monolayer and bilayer step of these materials by scanning tunneling microscopy (STM). These edges states are linearly dispersing protected by a large bulk gap spanning EF, robust against disorders and vertical stacking [2]. Based on these findings, we fabricate a novel “topological” STM tip with these materials, and show how the tunneling of the helical edge state becomes a metrological resource for atomic-scale spin sensing owing to the time-reversal-symmetry paired spin-momentum locking. As a stringent benchmark, we apply this helical tunneling spin probe to the layered altermagnetic material KV2Se2O and directly image the defining alternating spin texture in both real and momentum space [3].
[1] S. Phark et al., Nano Futures 9, 032001(2025);
[2] S. Yu et al., Phys. Rev. X 14, 041048 (2024);
[3] Z. Wang et al., arXiv: 2512.23290 (2025)
报告人简介：Professor Zhenyu Wang obtained his PhD from Institute of Physics, Chinese Academy of Sciences, in 2015. Then he held a postdoctoral appointment at the University of Illinois Urbana-Champaign, before joining the physics faculty at University of Science and Technology of China in 2019. He became a full professor of Physics in 2023. His research interests lie in the realm of quantum materials, including unconventional superconductors, Mott insulators and topological matters. His group uses the tool of STM to unravel the mysteries of these complex systems, and the fundamental goal is to directly visualize their emergent behaviors and manipulate their properties. Now Prof. Wang’s lab focuses on STM studies of topological superconductors and moiré superlattice where both electronic interactions and quantum geometry play the vital role in shaping their electronic properties.
主办：南京大学物理学院、江苏省物理学会、江苏省物理科学研究中心
联系人：张琦老师，zhangqi@nju.edu.cn
