Long-range corrected exchange-correlation kernels to describe excitons in second-harmonic generation

Nicolas Gauriot (1) , Valérie Véniard (2) , Eleonora Luppi (1)

1 LCT - Laboratoire de chimie théorique
2 LSI - Laboratoire des Solides Irradiés - Irradiated Solids Laboratory

We investigate the role of excitons in second-harmonic generation (SHG) through the long-range corrected (LRC) exchange-correlation kernels: empirical LRC, Bootstrap, and jellium-with-a-gap model. We calculate the macroscopic second-order frequency-dependent susceptibility χ(2). We also present the frequency-dependent macroscopic dielectric function ϵM which is a fundamental quantity in the theoretical derivation of χ(2). We assess the role of the long-range kernels in describing excitons in materials with different symmetry types: cubic zincblende, hexagonal wurtzite, and tetragonal symmetry. Our studies indicate that excitons play an important role in χ(2) bringing a strong enhancement of the SHG signal. Moreover, we found that the SHG enhancement follows a simple trend determined by the magnitude of the long-range corrected α-parameter. This trend is material dependent.

Domaines: Chimie-Physique [physics.chem-ph]

Nicolas Gauriot, Valérie Véniard, Eleonora Luppi. Long-range corrected exchange-correlation kernels to describe excitons in second-harmonic generation. Journal of Chemical Physics, 2019, 151 (23), pp.234111. ⟨10.1063/1.5126501⟩. ⟨hal-02442874⟩