Related papers: Huge excitonic effects in layered hexagonal boron …
Most semiconductors, in particular III-V compounds, have a complex valence band structure near the band edge, due to degeneracy at the zone center. One peculiar feature is the warping of the electronic dispersion relations, which are not…
We use a tight binding approach and density functional theory calculations to study the band structure of graphene/hexagonal boron nitride bilayer system in the most stable configuration. We show that an electric field applied in the…
We compute and track the impact of truly nonlocal-correlation effects on the quasi-particle (QP) band-structure of hexagonal boron-nitride (h-BN) systems. To that end, we start with the consistent-exchange vdW-DF-cx version [PRB 89, 035412…
Excitons are electron-hole pairs appearing below the band gap in insulators and semiconductors. They are vital to photovoltaics, but are hard to obtain with time-dependent density-functional theory (TDDFT), since most standard…
Optical excitations in hexagonal nanonetwork materials, for example, Boron-Nitride (BN) sheets and nanotubes, are investigated theoretically. A permanent electric dipole moment, whose direction is from the B site to the N site, is…
In this paper we theoretically describe the absorption of hexagonal boron nitride (hBN) single layer. We develop the necessary formalism and present an efficient method for solving the Wannier equation for excitons. We give predictions for…
In this Letter, we derive an effective theory of graphene on a hexagonal Boron Nitride (h-BN) substrate. We show that the h-BN substrate generically opens a spectral gap in graphene despite the lattice mismatch. The origin of that gap is…
Light emitters in wide band gap semiconductors are of great fundamental interest and have potential as optically addressable qubits. Here we describe the discovery of a new color center in high-quality hexagonal boron nitride (h-BN) with a…
We study the carbon dimer defect in a hexagonal boron-nitride monolayer using the GW and Bethe-Salpeter many-body perturbation theories within a finite size cluster approach. While quasiparticle energies converge very slowly with system…
This theoretical paper offers an explicit expression for the binding energy of excitons in a two-dimensional semiconductor with a flat valence band. The formula has been derived quasiclassically assuming that the exciton is tightly bound;…
Realizing direct-bandgap quantum dots working within the deep-ultraviolet frequency is highly desired for electro-optical and biomedical applications while remaining challenging. In this work, we combine the first-principles many-body…
Devising ways of opening a band gap in graphene to make charge-carrier masses finite is essential for many applications. Recent experiments with graphene on hexagonal boron nitride (h-BN) offer tantalizing hints that the weak interaction…
A study is presented of the electronic band structure and optical absorption spectrum of monolayer WSe$_2$ using an all-electron quasiparticle self-consistent $GW$ approach, QS$G\hat W$, in which the screened Coulomb interaction $\hat W$ is…
We report non-resonant x-ray Raman scattering (XRS) measurements from hexagonal boron nitride for transferred momentum from 2 to 9 $\mathrm{\AA}^{-1}$ along directions both in and out of the basal plane. A symmetry-based argument, together…
On the basis of many-body {\it ab-initio} calculations, using single-shot G$_0$W$_0$ method and Bethe-Salpeter equation, we study phosphorene nanoribbons (PNRs) in the two typical zigzag and armchair directions. The electronic structure,…
In this paper, we consider the spectral properties of the bilayer graphene with the local excitonic pairing interaction between the electrons and holes. We consider the generalized Hubbard model, which includes both intralayer and…
Metal monochalcogenide GaSe is a classic layered semiconductor that has received increasing research interest due to its highly tunable electronic and optical properties for ultrathin electronics applications. Despite intense research…
Absorption spectra, exciton energy levels and wave functions for solid Ne and Ar have been calculated from first principles using many-body techniques. Electronic band structures of Ne and Ar were calculated using the GW approximation.…
Here we describe an efficient numerical implementation of the Bethe-Salpeter equation to obtain the excitonic spectrum of semiconductors. This is done on the electronic structure calculated either at the simplest tight-binding level or…
Exciton-phonon interactions play a central role in defining the optical response of hexagonal boron nitride (hBN), yet their quantitative determination has remained incomplete. Here, we reveal the Fr\"ohlich-type exciton-phonon coupling in…