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arXiv · 2405.01371

k-resolved ultrafast light-induced band renormalization in monolayer WS$_2$ on graphene

Niklas Hofmann·Alexander Steinhoff·Razvan Krause·Neeraj Mishra·Giorgio Orlandini·Stiven Forti·Camilla Coletti·Tim O. Wehling·Isabella Gierz
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Abstract

Understanding and controlling the electronic properties of two-dimensional materials is crucial for their potential applications in nano- and optoelectronics. Monolayer transition metal dichalcogenides such as WS$_2$ have garnered significant interest due to their strong light-matter interaction and extreme sensitivity of the band structure to the presence of photogenerated electron-hole pairs. In this study, we investigate the transient electronic structure of monolayer WS$_2$ on a graphene substrate after resonant excitation of the A-exciton using time- and angle-resolved photoemission spectroscopy. We observe a pronounced band structure renormalization including a substantial reduction of the transient band gap that is in good quantitative agreement with our {\it ab initio} theory that reveals the importance of both intrinsic WS$_2$ and extrinsic substrate contributions to the transient band structure of monolayer WS$_2$. Our findings not only deepen the fundamental understanding of band structure dynamics in two-dimensional materials but also offer valuable insights for the development of novel electronic and optoelectronic devices based on monolayer TMDs and their heterostructures with graphene.

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Niklas Hofmann, Alexander Steinhoff, Razvan Krause, Neeraj Mishra, Giorgio Orlandini, Stiven Forti, Camilla Coletti, Tim O. Wehling, Isabella Gierz. 2024-05-02. k-resolved ultrafast light-induced band renormalization in monolayer WS$_2$ on graphene. https://doi.org/10.1021/acs.nanolett.4c06238

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