Related papers: Momentum dependence of the excitons in pentacene
The energy band structure of excitons is studied in periodic potentials produced by the short-range interaction between the exciton and electrons of Wigner or Moir\'{e} lattices. Treating the exciton as a point-like dipole that interacts…
We demonstrate that the valence energy-loss function of hexagonal boron nitride (hBN) displays a strong anisotropy in shape, excitation energy and dispersion for momentum transfer q parallel or perpendicular to the hBN layers. This is…
We investigate the impact on the properties of high-energy emitting BL Lac objects of a population of electrons with an anisotropic momentum distribution. We adopt a simple phenomenological description of the anisotropy, in which the most…
Precise understanding of the electronic structures of optically dark triplet-triplet multiexcitons that are the intermediate states in singlet fission (SF) continues to be a challenge. This is particularly true for intramolecular singlet…
We present it ab initio calculations of the electronic energy loss of charged particles moving outside a magnesium surface, from a realistic description of the one-electron band structure and a full treatment of the dynamical electronic…
We perform a $\mathbf{k \cdot p}$ theory analysis of the spectra of the lowest energy and excited states of the excitons in few-layer atomically thin films of InSe taking into account in-plane electric polarizability of the film and the…
We examine the excitonic properties of layered configurations of low dimensional transition metal dichalcogenides (LTMDCs) using the fractional dimensional space approach. The binding energies of the exciton, trion and biexciton in LTMDCs…
The structural and electronic properties of a single pentacene molecule and a pentacene molecular crystal, an organic semiconductor, are examined by a first-principles method based on the generalized gradient approximation of density…
We conduct polarization-dependent ultrafast spectroscopy to study the dynamics of singlet fission in tetracene single crystals. The spectrotemporal species for singlet and triplet excitons in transient absorption spectra are found to be…
Momentum resolved electron energy-loss spectroscopy was used to measure the dispersions of excitons in a free-standing monolayer of WSe2. Besides the parabolically dispersed valley excitons, a sub-gap dispersive exciton was observed at…
The magnetic field dependence of photoabsorption provides direct insights into the band structure of semiconductors. It is perhaps surprising that there is a large discrepancy between electron, hole, and reduced mass reported in the recent…
We have studied the low energy electronic excitations of C60 using momentum dependent electron energy-loss spectroscopy in transmission. The momentum dependent intensity of the gap excitation allows the first direct experimental…
The fission of singlet excitons into triplet pairs in organic materials holds great technological promise, but the rational application of this phenomenon is hampered by a lack of understanding of its complex photophysics. Here, we use the…
Electronic and optical excitations in two-dimensional moir\'e systems are uniquely sensitive to local atomic registries, leading to materials- and twist-angle specific correlated electronic ground states with varied degree of localization.…
The growing interest in exciton-polaritons has driven the need to manipulate their motion and engineer their band structures to the forefront of contemporary research. This study explores the band structures that emerge from a spatially…
We consider excitons in a two-dimensional periodic potential and study the linear response of the excitonic superfluid to an electromagnetic wave at low and high densities. It turns out that the static structure factor for small wavevectors…
The exchange effect and the magneto-plasmon mode dispersion are studied theoretically for an anisotropic two-dimensional electronic system in the presence of an uniform perpendicular magnetic field. Employing an effective low-energy model…
Self-assembled aggregates of pigment molecules are potential building blocks for excitonic circuits that find their application in energy conversion and optical signal processing. Recent experimental studies of one-dimensional…
We develop a new first-principles approach to predict and understand rates of singlet fission with an ab initio Green's-function formalism based on many-body perturbation theory. Starting with singlet and triplet excitons computed from a GW…
The full monolayer of pentacene adsorbed on rutile TiO$_2$(110) provides an intriguing model to study charge-transfer excitations where the optically excited electrons and holes reside on different sides of the internal interface between…