Efficient ab initio calculations of bound and continuum excitons

Francesco Sottile (1) , Marherita Marsili (1) , Valerio Olevano (2) , Lucia Reining (1)

1 LSI - Laboratoire des Solides Irradiés - Irradiated Solids Laboratory
2 NEEL - TMC - Théorie de la Matière Condensée

We present calculations of the absorption spectrum of semiconductors and insulators comparing various approaches: (i) the two-particle Bethe-Salpeter equation of Many-Body Perturbation Theory; (ii) time-dependent density-functional theory using a recently developed kernel that was derived from the Bethe-Salpeter equation; (iii) a scheme that we propose in the present work and that allows one to derive different parameter-free approximations to (ii). We show that all methods reproduce the series of bound excitons in the gap of solid argon, as well as continuum excitons in semiconductors. This is even true for the simplest static approximation, which allows us to reformulate the equations in a way such that the scaling of the calculations with number of atoms equals the one of the Random Phase Approximation.

Mots clés: time-dependent density-functional theory; exchange-correlation kernel; excitons

Domaines: Autre [cond-mat.other]; Science des matériaux [cond-mat.mtrl-sci]

Francesco Sottile, Marherita Marsili, Valerio Olevano, Lucia Reining. Efficient ab initio calculations of bound and continuum excitons. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2007, 76 (16), pp.161103(R). ⟨10.1103/PhysRevB.76.161103⟩. ⟨hal-00148138⟩