GRK seminar: Prof. Xiaoyang Zhu

Correlated Motions of Electrons, Spins, and Dipoles in 2D vdW Materials

Department of Chemistry, Columbia University, New York

Correlation plays a central role in emergent phenomena. Examples include, among others, quantum ground states and collective excitations. Here, I will discuss what we can learn
from time‐domain views of correlation in two dimensional (2D) vdW materials. In the 2D vdW magnetic semiconductor, CrSBr, excitonic transition is found to strongly couple to magnetic order [1] and this allows the easy detection of low energy (GHz‐THz) magnons by visible‐NIR light [2]. In twisted bilayer MoTe2,
we apply pump‐probe spectroscopy as hitherto the most sensitive probe of many‐body correlation in moiré quantum matter [3] to discover a zoo of quantum phases at fractional
fillings in moiré super‐lattices [4]. In the 2D vdW magnetic semiconductor, NbOI2 [5], we report the experimental discovery of a quasi‐particle, the ferron, which may form the basis for new modes of information processing and control [6].

[1] Nature Mater. 2021, 20, 1657‐1663.

[2] Nature 2022, 609, 282‐286.

[3] Phys. Rev. Lett. 2024, 132, 126501.

[4] Nature 2025, https://doi.org/10.1038/s41586‐025‐08954‐8.

[5] Nature Mat. 2025, https://doi.org/10.1038/s41563‐025‐
02201‐1.

[6] Manuscript submitted.

Venue: RUN auditorium