"Novel ultrafast phenomena in quantum materials enabled by charge transfer"
Charge transfer proved to be a simple while powerful tool for engineering collective excitations and phase transitions in quantum materials, both in and out of equilibrium. In this talk, I will talk about two cases in quantum material systems, where charge transfer give rise to exotic phenomena. For the first half, I will introduce a series of recent works on EuTe4, a new charge density wave (CDW) compound, where the intra unit cell charge transfer gives rise to a special CDW structure and further forms a robust 1D moiré superlattice. I will further introduce light-induced dynamics and potential applications enabled by the unique CDW structure. In the second half, I will introduce our latest results of magnon-plasmon coupling in NiPS3/graphene interfacial charge transfer device. Deploying near-field terahertz nanoscopy, we are able to map our the spacetime worldline of graphene plasmons across the antiferromagnetic (AFM) transition of NiPS3 underneath. Our results potentially indicates an unprecedented observation of plasmon renormalization due to interactions with AFM magnons.
