Related papers: Biexciton stability in carbon nanotubes
We report calculations of the energies of excitons and biexcitons in ideal two-dimensional bilayer systems within the effective-mass approximation with isotropic electron and hole masses. The exciton energies are obtained by a simple…
We show how lattice Quantum Monte Carlo can be applied to the electronic properties of carbon nanotubes in the presence of strong electron-electron correlations. We employ the path-integral formalism and use methods developed within the…
We propose a new type of hybrid systems formed by conventional semiconductor nanostructures with the addition of remote insulating layers, where the electron-hole interaction is enhanced by combining quantum and dielectric confinement over…
We develop a scaling relationship between the exciton binding energy and the external dielectric function in carbon nanotubes. We show that the electron-electron and electron-hole interaction energies are strongly affected by screening yet…
The carbon rich phase diagrams of nickel-carbon nanoparticles, relevant to catalysis and catalytic chemical vapor deposition synthesis of carbon nanotubes, are calculated for system sizes up to about 3 nanometers (807 Ni atoms). A tight…
Ground state diffusion Monte Carlo is used to investigate the binding energies and carrier probability distributions of excitons, trions, and biexcitons in a variety of two-dimensional transition metal dichalcogenide materials. We compare…
We demonstrate a possibility for exciton Bose-Einstein condensation in individual small-diameter (~1-2 nm) semiconducting carbon nanotubes. The effect occurs under the exciton-interband-plasmon coupling controlled by an external…
We study theoretically the optical properties of quantum tubes, one-dimensional semiconductor nanostructures where electrons and holes are confined to a cylindrical shell. In these structures, which bridge between 2D and 1D systems, the…
Resonant Raman spectroscopy of single carbon nanotubes suspended across trenches displays red shifts of up to 30 meV of the electronic transition energies as a function of the surrounding dielectric environment. We develop a simple scaling…
The exciton and biexciton binding energy have been studied for a ZnSe/ZnS core/shell quantum dot using WKB (Wentzel-Kramers-Brillouin) approximation. The exciton binding energy increases for small shell thickness and for large thickness,…
Luminescence properties of carbon nanotubes are strongly affected by exciton diffusion, which plays an important role in various nonradiative decay processes. Here we perform photoluminescence microscopy on hundreds of individual…
Deformations of single-wall carbon nanotubes are investigated within the tight-binding model with deformation-dependent hopping energies. We show that the nanotubes tend to twist and shrink spontaneously at zero temperature. The explicit…
A computational model is presented to calculate the ground state energy of neutral and charged excitons confined in semiconductor quantum dots. The model is based on the variational Quantum Monte Carlo method and effective mass…
The stability of a single-walled carbon nanotube placed on top of a catalytic nickel nanoparticle is investigated by means of molecular dynamics simulations. As a case study, we consider the $(12,0)$ nanotube consisting of 720 carbon atoms…
The optical absorption spectrum of the carbon (4,2) nanotube is computed using an ab-initio many-body approach which takes into account excitonic effects. We develop a new method involving a local basis set which is symmetric with respect…
We present a study of mono(benzene)TM and bis(benzene)TM systems, where TM={Mo,W}. We calculate the binding energies by quantum Monte Carlo (QMC) approaches and compare the results with other methods and available experiments. The orbitals…
The theory of exciton spectrum in multi-shell hexagonal semiconductor nanotube is developed within the effective masses and rectangular potentials approximations using the method of effective potential. It is shown that the exciton binding…
Single-walled carbon nanotubes exist in a variety of different geometries, so-called chiralities, that define their electronic properties. Chiral selectivity has been reported in catalytic chemical vapor deposition synthesis experiments,…
We investigate the binding of single and quadruple hydrogen molecules on a positively charged Ca ion. By comparing with benchmark quantum Monte Carlo (QMC) calculations we demonstrate wide variability in other more approximate electronic…
Ultraclean, undoped carbon nanotubes are observed to be always insulating, even when the gap predicted by band theory is zero: the residual band gap is then thought to have a many-body origin. Here we theoretically show that the correlated…