Work

Strain Control of Valley Polarization Dynamics in a 2D Semiconductor via Exciton Hybridization

Year: 2025

Type: article

Abstract: Encoding and manipulating digital information in quantum degrees of freedom is one of the major challenges of today's science and technology. The valley indices of excitons in transition metal dichalcogenides (TMDs) are well-suited to addressing this challenge. Here, we employ mechanical strain to manipulate intervalley interactions and tune the valley polarization dynamics of excitons across a broader range of momentum space in monolayer TMDs. We use strain engineering to form valley-hybridized excitons that combine the advantages of bright intravalley excitons, where the valley index directly couples to light polarization, and dark intervalley excitons, characterized by low depolarization rates. We demonstrate that these valley-hybridized excitons exhibit signatures of coherently coupled states with a 100-fold reduction in valley depolarization rate and up to a 5-fold increase in steady-state valley polarization compared to previously studied excitons. Our findings of strain-tunable valley character of excitons advance the applications of TMDs in valleytronics.

Source: Nano Letters

DOI: 10.1021/acs.nanolett.5c02636

Authors: Abhijeet M. Kumar, Douglas J. Bock, Denis Yagodkin, Edith Wietek, Bianca Höfer, Max Sinner, Adrián Dewambrechies, Pablo Hernández López, Sviatoslav Kovalchuk, Raghav Dhingra, Sebastian Heeg, Cornelius Gahl, Florian Libisch, Alexey Chernikov, Ermin Malic, Roberto Rosati, Kirill I. Bolotin

Institutions: Freie Universität Berlin, Complexity, Topology and Dynamics in Quantum Matter, Technische Universität Dresden, TU Wien, University of Luxembourg, Humboldt-Universität zu Berlin, Philipps University of Marburg

Language: English

Topic: 2D Materials and Applications

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funders: Deutsche Forschungsgemeinschaft, Bundesministerium für Bildung und Forschung, Austrian Science Fund, Freie Universität Berlin, H2020 European Research Council

Awards: Verbundprojekt 05K2022 - ioARPES: Echtzeit micro-ARPES für die in-operando einstellbare Untersuchung von Material- und Bauelementeigenschaften. Teilprojekt 2., Quantengase in Moirégeordneten und rekonstruierten Heterostrukturen: Effektive Dimensionalitäten, Hybridzustände und Wechselwirkungen, G1544390775, G1684925124, G2152757567, G2350469352, Untersuchung und Kontrolle elektronischer Vielteilchenzustände in zweidimensionalen Materialien, G4234687218, G4285518817, G4846862643, Coulomb Engineering of Quantum States in Matter, G543524628, G5536861278, G6073443781, ExzitonTransport in atomar dünnen Halbleitern bei tiefen Temperaturen, Carbin für Optoelektronik und Optomechanik, G8584211994, SFB 1277: Emergente relativistische Effekte in der Kondensierten Materie: Von grundlegenden Aspekten zu elektronischer Funktionalität, G977229675

OpenAlex ID: W4415114559

FWCI: 2.481

Cites: 71

Cited by: 12

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