Research paperExperimental CharacterizationTheoreticalExciton dispersion fine structure and deep ultraviolet optical conductivity of freestanding two-dimensional h-BNJinhua Hong, Alberto Guandalini, Weibin Wu, Haiming Sun et al.arXiv preprint·2025·10.1038/s41699-017-0003-9·arXiv:2510.08397AbstractMomentum-resolved electron energy loss spectroscopy (q-EELS) is used to probe exciton dispersions in mono- and few-layer freestanding hexagonal boron nitride. The work reveals a fine structure of the first bright exciton band composed of two features (A and A′) at small momentum, with a splitting of about 0.25 eV, and a linearly dispersive B exciton. Using an optical conductivity approximation, the authors extract deep-UV optical conductivity at zero momentum from low-q EELS spectra and compare it with beyond-GW-BSE calculations. The A′ satellite weakens with increasing thickness, suggesting the strongest exciton-phonon coupling in the monolayer limit.Read more
Freestanding monolayer h-BN used for q-EELS and ADF-STEM measurements.1 preparation2 characterizations3 properties2 figuresExperimentalh-BNStudied MaterialExpand
Freestanding few-layer h-BN used for thickness-dependent q-EELS comparisons.1 characterization2 figuresExperimentalh-BNStudied MaterialExpand
Research paperExperimental CharacterizationTheoreticalExciton dispersion fine structure and deep ultraviolet optical conductivity of freestanding two-dimensional h-BNJinhua Hong, Alberto Guandalini, Weibin Wu, Haiming Sun et al.arXiv preprint·2025·10.1038/s41699-017-0003-9·arXiv:2510.08397AbstractMomentum-resolved electron energy loss spectroscopy (q-EELS) is used to probe exciton dispersions in mono- and few-layer freestanding hexagonal boron nitride. The work reveals a fine structure of the first bright exciton band composed of two features (A and A′) at small momentum, with a splitting of about 0.25 eV, and a linearly dispersive B exciton. Using an optical conductivity approximation, the authors extract deep-UV optical conductivity at zero momentum from low-q EELS spectra and compare it with beyond-GW-BSE calculations. The A′ satellite weakens with increasing thickness, suggesting the strongest exciton-phonon coupling in the monolayer limit.Read more
Freestanding monolayer h-BN used for q-EELS and ADF-STEM measurements.1 preparation2 characterizations3 properties2 figuresExperimentalh-BNStudied MaterialExpand
Freestanding few-layer h-BN used for thickness-dependent q-EELS comparisons.1 characterization2 figuresExperimentalh-BNStudied MaterialExpand
Research paperExperimental CharacterizationTheoreticalExciton dispersion fine structure and deep ultraviolet optical conductivity of freestanding two-dimensional h-BNJinhua Hong, Alberto Guandalini, Weibin Wu, Haiming Sun et al.arXiv preprint·2025·10.1038/s41699-017-0003-9·arXiv:2510.08397AbstractMomentum-resolved electron energy loss spectroscopy (q-EELS) is used to probe exciton dispersions in mono- and few-layer freestanding hexagonal boron nitride. The work reveals a fine structure of the first bright exciton band composed of two features (A and A′) at small momentum, with a splitting of about 0.25 eV, and a linearly dispersive B exciton. Using an optical conductivity approximation, the authors extract deep-UV optical conductivity at zero momentum from low-q EELS spectra and compare it with beyond-GW-BSE calculations. The A′ satellite weakens with increasing thickness, suggesting the strongest exciton-phonon coupling in the monolayer limit.Read more
Freestanding monolayer h-BN used for q-EELS and ADF-STEM measurements.1 preparation2 characterizations3 properties2 figuresExperimentalh-BNStudied MaterialExpand
Freestanding few-layer h-BN used for thickness-dependent q-EELS comparisons.1 characterization2 figuresExperimentalh-BNStudied MaterialExpand
Research paperExperimental CharacterizationTheoreticalExciton dispersion fine structure and deep ultraviolet optical conductivity of freestanding two-dimensional h-BNJinhua Hong, Alberto Guandalini, Weibin Wu, Haiming Sun et al.arXiv preprint·2025·10.1038/s41699-017-0003-9·arXiv:2510.08397AbstractMomentum-resolved electron energy loss spectroscopy (q-EELS) is used to probe exciton dispersions in mono- and few-layer freestanding hexagonal boron nitride. The work reveals a fine structure of the first bright exciton band composed of two features (A and A′) at small momentum, with a splitting of about 0.25 eV, and a linearly dispersive B exciton. Using an optical conductivity approximation, the authors extract deep-UV optical conductivity at zero momentum from low-q EELS spectra and compare it with beyond-GW-BSE calculations. The A′ satellite weakens with increasing thickness, suggesting the strongest exciton-phonon coupling in the monolayer limit.Read more
Freestanding monolayer h-BN used for q-EELS and ADF-STEM measurements.1 preparation2 characterizations3 properties2 figuresExperimentalh-BNStudied MaterialExpand
Freestanding few-layer h-BN used for thickness-dependent q-EELS comparisons.1 characterization2 figuresExperimentalh-BNStudied MaterialExpand