April 22 - 26, 2024
Seattle, Washington
May 7 - 9, 2024 (Virtual)

Event Supporters

2024 MRS Spring Meeting
QT03.07.09

Dynamical Coulomb Screening in Atomically Thin Semiconducting Transition Metal Dichalcogenides

When and Where

Apr 25, 2024
4:45pm - 5:00pm
Room 444, Level 4, Summit

Presenter(s)

Co-Author(s)

Amine Ben Mhenni1,2,Dinh Van Tuan3,Leonard Geilen1,2,Marko Petrić1,2,Kenji Watanabe4,Takashi Taniguchi4,Sefaattin Tongay5,Kai Müller1,2,Nathan Wilson1,2,Jonathan Finley1,2,Hanan Dery3,Matteo Barbone1,2

Technical University of Munich1,Munich Center for Quantum Science and Technology (MCQST)2,University of Rochester3,National Institute for Materials Science4,Arizona State University5

Abstract

Amine Ben Mhenni1,2,Dinh Van Tuan3,Leonard Geilen1,2,Marko Petrić1,2,Kenji Watanabe4,Takashi Taniguchi4,Sefaattin Tongay5,Kai Müller1,2,Nathan Wilson1,2,Jonathan Finley1,2,Hanan Dery3,Matteo Barbone1,2

Technical University of Munich1,Munich Center for Quantum Science and Technology (MCQST)2,University of Rochester3,National Institute for Materials Science4,Arizona State University5
Reduced screening contributes to the particularly strong Coulomb interaction characteristic of 2D materials<sup>1</sup>, which is behind the emergence of exotic quantum many-body phases found therein. While the 2D nature of these material systems complicates the screening description, its understanding is, to date, considered well-established, mainly based on static approaches<sup>2</sup>. Here, we use exciton resonances as probes to study screening in monolayer WSe<sub>2</sub>, which we embed in dielectric environments with dielectric constants ranging from 5 to more than 1000. At odds with previous reports<sup>3</sup>, we find evidence for an optical bandgap <i>blueshift </i>for larger dielectric constants. We understand the experimental findings by developing a fully dynamical approach to the environment dielectric response. Starting from the 3χ model<sup>4</sup>, we take the frequency dependence into account via the dynamical dielectric function, both in the bandgap renormalization and in the exciton binding energy calculations. While binding energy remains mainly controlled by low-frequency dielectric screening, we find that high-frequency dielectric response is predominant in bandgap renormalization. Our results show that a fundamental understanding of Coulomb interaction in atomically thin materials cannot ignore dynamical effects. The achieved tunability of the optical bandgap by more than 30 meV, together with the qualitatively different theoretical framework developed, offer new opportunities for tuning the optoelectronic properties of 2D semiconductors and advance the study of many-body interactions in layered materials and their heterostructures.<br/><br/>References:<br/><sup>1 </sup>Chernikov, A., Berkelbach, T. C., Hill, H. M., Rigosi, A., Li, Y., Aslan, B., Reichman, D. R., Hybertsen, M. S., & Heinz, T. F. (2014a). Exciton binding energy and nonhydrogenic Rydberg series in monolayer WS<sub>2</sub>. Physical Review Letters, 113(7).<br/><sup>2 </sup>Cho, Y., & Berkelbach, T. C. (2018). Environmentally sensitive theory of electronic and optical transitions in atomically thin semiconductors. Physical Review B, 97(4).<br/><sup>3 </sup>Raja, A., Chaves, A., Yu, J., Arefe, G., Hill, H. M., Rigosi, A. F., Berkelbach, T. C., Nagler, P., Schüller, C., Korn, T., Nuckolls, C., Hone, J., Brus, L. E., Heinz, T. F., Reichman, D. R., & Chernikov, A. (2017). Coulomb engineering of the bandgap and excitons in two-dimensional materials. Nature Communications, 8(1).<br/><sup>4 </sup>Van Tuan, D., Yang, M., & Dery, H. (2018). Coulomb interaction in monolayer transition-metal dichalcogenides. Physical Review B, 98(12).

Keywords

2D materials

Symposium Organizers

Michal Baranowski, Wroclaw University of Science and Technology
Alexey Chernikov, Technische Universität Dresden
Paulina Plochocka, CNRS
Alexander Urban, LMU Munich

Symposium Support

Bronze
LIGHT CONVERSION
Wroclaw University of Science and Technology

Session Chairs

Alexey Chernikov
Milan Delor

In this Session