Related papers: Coherent-potential-approximation study of excitoni…
A phenomenological coupled exciton model is proposed in order to characterize optical excitations in extended dendrimers. An onsite exciton state is assigned at each phenyl rings and a nearest neighbor hopping integral which obeys the…
The density of states, even for a perfectly ordered tight-binding model, can exhibit a tail-like feature at the top of the band, provided the hopping integral falls off in space slowly enough. We apply the coherent potential approximation…
We investigate strongly asymmetric self-assembled nanostructures with one of dimensions reaching hundreds of nanometers. Close to the nanowire-like type of confinement, such objects are sometimes assigned as one-dimensional in nature. Here,…
Absorption of electromagnetic energy by a material is a phenomenon that underlies many applied problems, including molecular sensing, photocurrent generation and photodetection. Commonly, the incident energy is delivered to the system…
We compute the DC and the optical conductivity of graphene for finite values of the chemical potential by taking into account the effect of disorder, due to mid-gap states (unitary scatterers) and charged impurities, and the effect of both…
We develop a formulation of the coherent potential approximation (CPA) on the basis of the Wannier representation to develop a computationally efficient method for the treatment of homogeneous random alloys that is independent on the…
Angular x-ray cross-correlation analysis (XCCA) is an approach to study the structure of disordered systems using the results of coherent x-ray scattering experiments. Here, we present the results of simulations that validate our…
Computationally tractable and reliable, albeit approximate, methods for studying exciton transport in molecular aggregates immersed in structured bosonic environments have been actively developed. Going beyond the lowest-order (Born)…
We extend the static theory of disorder-induced exponential decay of the averaged Green function of a quantum charged particle in a classical one-component plasma to the dynamic regime by incorporating the temporal evolution of the ionic…
Quenched disorder - in the sense of the Harris criterion - is generally a relevant perturbation at an absorbing state phase transition point. Here using a strong disorder renormalization group framework and effective numerical methods we…
On the optical absorption and the density of states of Frenkel exciton systems on square, rectangular, and triangular lattices with nearest-neighbor interactions and a Gaussian distribution of transition frequencies. The analysis is based…
A new microscopic approach to the optical transitions in quantum dots and quantum dot molecules, which accounts for both diagonal and non-diagonal exciton-phonon interaction, is developed. The cumulant expansion of the linear polarization…
We apply the optimal fluctuation method to the calculation of the optical absorption in disordered one-dimensional semiconductors below the fundamental optical gap. We find that a photon energy exists at which the shape of the optimal…
The cross-over from coherent to incoherent exciton transport in disordered polymer films is studied by computationally solving a modified form of the Redfield equation for the exciton density matrix. This theory models quantum mechanical…
The interaction of excitons with lattice vibrations underlies the scattering from bright to dark excitons as well as the coherent modulation of the exciton energy. Unlike the former mechanism, which involves phonons with finite momentum,…
We calculate, as a function of temperature and conduction band electron density, the optical absorption of a weakly n-doped, idealized semiconductor quantum well. In particular, we focus on the absorption band due to the formation of a…
The CP decomposition for high dimensional non-orthogonal spiked tensors is an important problem with broad applications across many disciplines. However, previous works with theoretical guarantee typically assume restrictive incoherence…
The coherent potential approximation has historically allowed the efficient study of disorder effects over a variety of solid state systems. Its original formulation is however limited to a single-site or uncorrelated model of local…
We present an asymmetric bifacial graphene metasurface to realize tunable and broadband coherent perfect absorption (CPA) at terahertz (THz) frequencies. The proposed design is composed of two dissimilar graphene square patch metasurfaces…
We present a longitudinal electrical conductivity calculation method for disordered alloys applicable from a wide range of density functional theory (DFT) codes based on the first-principles Wannier-based coherent potential approximation…