Observation of ultrafast interfacial Meitner-Auger energy transfer in a van der Waals heterostructure - Archive ouverte HAL Accéder directement au contenu
Pré-Publication, Document De Travail Année : 2022

Observation of ultrafast interfacial Meitner-Auger energy transfer in a van der Waals heterostructure

Résumé

Atomically thin layered van der Waals heterostructures feature exotic and emergent optoelectronic properties. With growing interest in these novel quantum materials, the microscopic understanding of fundamental interfacial coupling mechanisms is of capital importance. Here, using multidimensional photoemission spectroscopy, we provide a layer- and momentum-resolved view on ultrafast interlayer electron and energy transfer in a monolayer-WSe$_2$/graphene heterostructure. Depending on the nature of the optically prepared state, we find the different dominating transfer mechanisms: while electron injection from graphene to WSe$_2$ is observed after photoexcitation of quasi-free hot carriers in the graphene layer, we establish an interfacial Meitner-Auger energy transfer process following the excitation of excitons in WSe$_2$. By analysing the time-energy-momentum distributions of excited-state carriers with a rate-equation model, we distinguish these two types of interfacial dynamics and identify the ultrafast conversion of excitons in WSe$_2$ to valence band transitions in graphene. Microscopic calculations find interfacial dipole-monopole coupling underlying the Meitner-Auger energy transfer to dominate over conventional F\"orster- and Dexter-type interactions, in agreement with the experimental observations. The energy transfer mechanism revealed here might enable new hot-carrier-based device concepts with van der Waals heterostructures.

Dates et versions

hal-03797255 , version 1 (04-10-2022)

Identifiants

Citer

Shuo Dong, Samuel Beaulieu, Malte Selig, Philipp Rosenzweig, Dominik Christiansen, et al.. Observation of ultrafast interfacial Meitner-Auger energy transfer in a van der Waals heterostructure. 2022. ⟨hal-03797255⟩

Collections

CEA CNRS DAM
18 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More