Indirect excitons and electron-phonon interaction in hexagonal boron nitride

Guillaume Cassabois (1)

1 L2C - Laboratoire Charles Coulomb

I will discuss our recent experiments by two-photon spectroscopy demonstrating that hBN is an indirect bandgap material. I will show that the optical properties of hBN are profoundly determined by phonon-assisted transitions involving either virtual or real excitonic states. I will present our measurements of the exciton binding energy by two-photon excitation, leading to the estimation of 6.08 eV for the single-particle bandgap in hBN. I will also discuss our experimental evidence that transverse optical phonons at the K point of the Brillouin zone assist inter-K valley scattering in hexagonal boron nitride.

Domaines: Autre [cond-mat.other]

Guillaume Cassabois. Indirect excitons and electron-phonon interaction in hexagonal boron nitride. ICPS2016, Aug 2016, Beijing, China. ⟨hal-01358453⟩