Ab initio electronic and excitonic properties of pristine and defected van der Waals matter

CIC nanoGUNE Seminars

Daniel Hernangómez
CIC nanoGUNE Seminar room, Tolosa Hiribidea 76, Donostia-San Sebastian
Emilio Artacho
Add to calendar
Subscribe to Newsletter
Ab initio electronic and excitonic properties of pristine and defected van der Waals matter

In recent years, a significant effort has been devoted to the study of physical mechanisms involved in the electronic, magnetic and optical properties of van der Waals materials. These materials are expected to play an important role in emergent ultrathin photovoltaic, optoelectronic and photocatalytic applications. Theoretical ab initio studies can help to shed light on the properties of these materials, and how they are affected by different microscopic factors such as defects, structural complexity, reduced dimensionality or interface composition.

In this talk, I will be using first principles to discuss some of those properties, specifically focusing on transition-metal dichalcogenides (TMDC) and TMDC-graphene interfaces. I will examine the effects of atomic-size defects on the optical and magneto-optical properties of these materials, and demonstrate how the presence of defects produce a structurally controllable excitonic magneto-optical response [1-3]. Additionally, I will discuss the charge transfer and excitonic effects at the TMDC-graphene interface. Defects can create a slow coherent transport channel for interlayer charge transfer [4] while also drastically altering the excitonic properties of the heterostructures compared to the pristine counterparts [5-6].

[1] E. Mitterreiter, B. Schuler, A. Micevic, D. Hernangómez-Pérez, et al. Nat. Comm. 12, 3822 (2021).
[2] T. Amit, D. Hernangómez-Pérez, G. Cohen, D. Y. Qiu, and S. Refaely-Abramson, Phys. Rev. B 106, L161407 (2022).
[3] A. Hötger, T. Amit, J. Klein, et al. npj 2D Mater. Appl. 7, 30 (2023).
[4] D. Hernangómez-Pérez, A. Donarini, and S. Refaely-Abramson, Phys. Rev. B 107, 075417 (2023). Editors' Suggestion.
[5] D. Hernangómez-Pérez, A. Kleiner, and S. Refaely-Abramson, Nano Lett. 13, 5995 (2023).
[6] A. Kleiner, D. Hernangómez-Pérez, and S. Refaely-Abramson, arXiv:2401.17928 (2024).