Optical properties of bulk semiconductors and graphene/boron-nitride: The Bethe-Salpeter equation with derivative discontinuity-corrected DFT energies

Abstract

We present an efficient implementation of the Bethe-Salpeter equation (BSE) for optical properties of materials in the projector augmented wave method GPAW. Single-particle energies and wave functions are obtained from the GLLBSC functional which explicitly includes the derivative discontinuity, is computationally inexpensive, and yields excellent fundamental gaps. Electron-hole interactions are included through the BSE using the statically screened interaction evaluated in the random phase approximation. For a representative set of semiconductors and insulators we find excellent agreement with experiments for the dielectric functions, onset of absorption, and lowest excitonic features. For the two-dimensional systems of graphene and hexagonal boron-nitride (h-BN) we find good agreement with previous many-body calculations. For the graphene/h-BN interface, we find that the fundamental and optical gaps of the h-BN layer are reduced by 2.0 eV and 0.7 eV, respectively, compared to freestanding h-BN. This reduction is due to image charge screening which shows up in the GLLBSC calculation as a reduction (vanishing) of the derivative discontinuity.

12 pages, 2 tables, 5 figures

References in corpus (6)

• Boron nitride substrates for high-quality graphene electronics
• Renormalization of Molecular Electronic Levels at Metal-Molecule Interfaces
• Excitonic Effects on the Optical Response of Graphene and Bilayer Graphene
• {\it Ab--initio} finite temperature excitons
• Linear density response function in the projector-augmented wave method: Applications to solids, surfaces, and interfaces
• Dielectric anisotropy in the GW space-time method

Cited by in corpus (8)

• GPAW: An open Python package for electronic-structure calculations
• A method to restore the intrinsic dielectric functions of 2D materials in periodic calculations and its applications to the dielectric and optical properties of ultrathin h-BN and MoS2
• Ab initio study of electromagnatic modes in two-dimensional semiconductors: Application to doped phosphorene
• Gap control in phosphorene/BN structures from first principles calculations
• Cavity exciton-polaritons in two-dimensional semiconductors from first principles
• Electron energy-loss spectrum and exciton band structure of ${\mathrm{WSe}}_2$ monolayer studied by ab initio Bethe-Salpeter equation calculations
• Chemical potential, derivative discontinuity, fractional electrons, jump of the Kohn-Sham potential, atoms as thermodynamic open systems, and other (mis)conceptions of the density functional theory of electrons in molecules
• Strong 1D localization and highly anisotropic electron-hole masses in heavy-halogen functionalized graphenes