Supplementary data for the article "Doping-control of excitons and magnetism in few-layer CrSBr"

Magnetism in two-dimensional materials reveals phenomena distinct from bulk magnetic crystals, with sensitivity to charge doping and electric fields in monolayer and bilayer van der Waals magnet CrI3. Within the class of layered magnets, semiconducting CrSBr stands out by featuring stability under ambient conditions, correlating excitons with magnetic order and thus providing strong magnon-exciton coupling, and exhibiting peculiar magneto-optics of exciton-polaritons. Here, we demonstrate that both exciton and magnetic transitions in bilayer and trilayer CrSBr are sensitive to voltage-controlled field-effect charging, exhibiting bound exciton-charge complexes and doping-induced metamagnetic transitions. Moreover, we demonstrate how these unique properties enable optical probes of local magnetic order, visualizing magnetic domains of competing phases across metamagnetic transitions induced by magnetic field or electrostatic doping. Our work identifies few-layer CrSBr as a rich platform for exploring collaborative effects of charge, optical excitations, and magnetism.二维材料中的磁学现象与块体磁晶体存在显著差异，单层及双层范德瓦尔斯（van der Waals）磁体CrI₃的磁学性质对电荷掺杂与电场具有敏感性。在层状磁体家族中，半导体性CrSBr脱颖而出：其可在环境条件下稳定存在，能够将激子与磁序相关联，进而实现强磁振子-激子耦合效应，并展现出激子极化激元独特的磁光学特性。本研究表明，双层与三层CrSBr中的激子跃迁与磁跃迁均对电压调控的场效应充电具有响应，可观测到束缚激子-电荷复合体以及掺杂诱导的变磁转变。此外，本研究还展示了如何借助这些独特性质实现局域磁序的光学探测，直观呈现磁场或静电掺杂诱导的变磁转变过程中竞争相的磁畴结构。本研究确认少层CrSBr是探索电荷、光学激发与磁学协同效应的优质研究平台。