Charge Transfer Dynamics in WS₂/NiPS₃ Heterostructures

Magnetic van der Waals (vdW) heterostructures (HSs), whose interface engineering enables versatile manipulation of charge and spin transfer, have received considerable interest. However, the dynamics underlying these exotic interfacial phenomena require deeper investigation. In this work, we investigated the interfacial charge transfer dynamics in a HS comprising layered antiferromagnetic NiPS₃ and transition metal dichalcogenide WS₂. Under resonant excitation of WS₂, we observed significant enhancement of the <i>d</i>-<i>d</i> transition in NiPS₃, driven by the charge transfer from the WS₂ to Ni 3<i>d</i> orbital. Additionally, an anomalous enhancement of trion emission in WS₂ was observed, accompanied by a relatively slow (∼23 ps) charge transfer from NiPS₃ to WS₂, attributed to the localized feature of Ni 3<i>d</i> orbitals. Our findings highlight the unique localization property of the <i>d</i>-orbital in magnetic materials and provide valuable insights into the interfacial dynamics of magnetic vdW HS, which are fundamentally important for designing novel devices.