Link between interlayer hybridization and ultrafast charge transfer in WS 2 -graphene heterostructures

Ultrafast charge separation after photoexcitation is a common phenomenon in various van-der-Waals (vdW) heterostructures with great relevance for future applications in light harvesting and detection. Theoretical understanding of this phenomenon converges towards a coherent mechanism through charge transfer states accompanied by energy dissipation into strongly coupled phonons. The detailed microscopic pathways are material specific as they sensitively depend on the band structures of the individual layers, the relative band alignment in the heterostructure, the twist angle between the layers, and interlayer interactions resulting in hybridization. We used time- and angle-resolved photoemission spectroscopy combined with tight binding and density functional theory electronic structure calculations to investigate ultrafast charge separation and recombination in WS2-graphene vdW heterostructures. We identify several avoided crossings in the band structure and discuss their relevance for ultrafast charge transfer. We relate our own observations to existing theoretical models and propose a unified picture for ultrafast charge transfer in vdW heterostructures where band alignment and twist angle emerge as the most important control parameters.

Weigl, LeonardUniversität Regensburg,University of Regensburg (författare)
Gradl, JohannesUniversität Regensburg,University of Regensburg (författare)
Mishra, NeerajCenter for Nanotechnology Innovation (CNI),Fondazione Istituto Italiano di Tecnologia (författare)
Orlandini, GiorgioCenter for Nanotechnology Innovation (CNI) (författare)
Forti, StivenCenter for Nanotechnology Innovation (CNI) (författare)
Coletti, CamillaCenter for Nanotechnology Innovation (CNI),Fondazione Istituto Italiano di Tecnologia (författare)
Latini, SimoneDanmarks Tekniske Universitet,Technical University of Denmark (författare)
Xian, Lede (författare)
Rubio, AngelMax Planck Gesellschaft zur Förderung der Wissenschaften e.V. (MPG),Max Planck Society for the Advancement of Science (MPG) (författare)
Paredes, Dilan PerezPhilipps-Universität Marburg,Philipps University Marburg (författare)
Perea Causin, Raul,1995Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)causin (författare)
Brem, Samuel,1991Philipps-Universität Marburg,Philipps University Marburg(Swepub:cth)brem (författare)
Malic, Ermin,1980Philipps-Universität Marburg,Philipps University Marburg,Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)ermin (författare)
Gierz, I.Universität Regensburg,University of Regensburg (författare)
Universität RegensburgCenter for Nanotechnology Innovation (CNI) (creator_code:org_t)

Av författaren/redakt...: Hofmann, Niklas; Weigl, Leonard; Gradl, Johannes; Mishra, Neeraj; Orlandini, Giorg ...; Forti, Stiven; visa fler...; Coletti, Camilla; Latini, Simone; Xian, Lede; Rubio, Angel; Paredes, Dilan P ...; Perea Causin, Ra ...; Brem, Samuel, 19 ...; Malic, Ermin, 19 ...; Gierz, I.; visa färre...

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