Exciton Self-Trapping in Twisted Hexagonal Boron Nitride homostructures

Sébastien Roux; Christophe Arnold; Etienne Carré; Alexandre Plaud; Lei Ren; Frédéric Fossard; Nicolas Horezan; Eli Janzen; James H. Edgar; Camille Maestre; Bérangère Toury; Catherine Journet; Vincent Garnier; Philippe Steyer; Takashi Taniguchi; Kenji Watanabe; Cédric Robert; Xavier Marie; François Ducastelle; Annick Loiseau; Julien Barjon

doi:10.1103/physrevx.15.021067

Journal article Exciton Self-Trapping in Twisted Hexagonal Boron Nitride homostructures

; ; ; ; ; ; ; ; ; ; ; ; ; ;

;

; ; ; ; ;

Download file (3.34 MB)
Download as zip (2.97 MB)

Collection

Citation

Sébastien Roux, Christophe Arnold, Etienne Carré, Alexandre Plaud, Lei Ren, Frédéric Fossard, Nicolas Horezan, Eli Janzen, James H. Edgar, Camille Maestre, Bérangère Toury, Catherine Journet, Vincent Garnier, Philippe Steyer, Takashi Taniguchi, Kenji Watanabe, Cédric Robert, Xavier Marie, François Ducastelle, Annick Loiseau, Julien Barjon. Exciton Self-Trapping in Twisted Hexagonal Boron Nitride homostructures. Physical Review X. 2025, 15 (2), 021067. https://doi.org/10.1103/physrevx.15.021067

(BibTeX)

Description:

(abstract)

One of the primary interests of 2D materials is that their atomic layers can be assembled with various degrees of freedom, allowing for tunable excitonic properties. Understanding how interlayer interfaces affect excitons is crucial. In this study, cathodoluminescence and time-resolved cathodoluminescence reveal how excitons interact with the interface between two twisted hexagonal boron nitride (h-BN) crystals at different angles. The interface efficiently captures free excitons, resulting in a population of long-lived, interface-localized (2D) excitons. Temperature-dependent measurements show that, at large twist angles, these interface-localized excitons undergo self-trapping caused by lattice distortion around the exciton. This exciton-interface interaction is responsible for the broad 4-eV optical emission of highly twisted h-BN/h-BN structures. Exciton self-trapping is discussed as a common trait in sp²-hybridized boron nitride polytypes and nanostructures, due to the ionic nature of the B–N bond and the small size of the excitons.

Rights: