Skip to Main content Skip to Navigation
Journal articles

Exciton interference in hexagonal boron nitride

Abstract : In this letter we report a thorough analysis of the exciton dispersion in bulk hexagonal boron nitride. We solve the ab initio GW Bethe-Salpeter equation at finite q ΓK, and we compare our results with recent high-accuracy electron energy loss data. Simulations reproduce the measured dispersion and the variation of the peak intensity. We focus on the evolution of the intensity, and we demonstrate that the excitonic peak is formed by the superposition of two groups of transitions that we call KM and M K from the k-points involved in the transitions. These two groups contribute to the peak intensity with opposite signs, each damping the contributions of the other. The variations in number and amplitude of these transitions determine the changes in intensity of the peak. Our results contribute to the understanding of electronic excitations in this systems along the ΓK direction, which is the relevant direction for spectroscopic measurements. They also unveil the non-trivial relation between valley physics and excitonic dispersion in h–BN, opening the possibility to tune excitonic effects by playing with the interference between transitions. Furthermore, this study introduces analysis tools and a methodology that are completely general. They suggest a way to regroup independent-particle transitions which could permit a deeper understanding of excitonic properties in any system.
Complete list of metadata

Cited literature [16 references]  Display  Hide  Download

https://hal.archives-ouvertes.fr/hal-01635495
Contributor : Claudio Attaccalite Connect in order to contact the contributor
Submitted on : Wednesday, November 15, 2017 - 11:38:07 AM
Last modification on : Wednesday, November 3, 2021 - 7:59:20 AM
Long-term archiving on: : Friday, February 16, 2018 - 2:37:31 PM

File

1709.07397.pdf
Files produced by the author(s)

Identifiers

Collections

Citation

Lorenzo Sponza, Hakim Amara, François Ducastelle, Annick Loiseau, Claudio Attaccalite. Exciton interference in hexagonal boron nitride. Physical Review B, American Physical Society, 2018, 97 (7), pp.075121. ⟨10.1103/PhysRevB.97.075121⟩. ⟨hal-01635495⟩

Share

Metrics

Record views

181

Files downloads

63