Influence Of Dielectric Environment Research Articles

The Influence of Dielectric Environment on Spectral Shift of Localized Plasmonic Resonance

In paper the investigation results of dielectric environment influences on spectral shift of localized plasmonic resonance in a system of self-assembled metallic nanoparticles was introduced. It was shown, that the value of spectral shift of localized plasmonic resonance has a linear proportion towards the changes of environment refractive index. For investigated plasmonic system of self-assembled Au nanoparticles the coefficient of proportionality was determined.

The influence of dielectric environment on the localized surface plasmon resonance of silver-based composite thin films

Ag-based thin films with different topography were prepared by annealing process and laser irradiation, respectively. The tunability of localized surface plasmon resonance (LSPR) was realized by adjusting the cover layer thickness of ITO or TiO2. The effect of dielectric environment of Ag-based composite thin films on structure, surface morphology and optical property was investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM), UV-VIS-NIR double beam spectrometer and Raman system, respectively. With the thickness of dielectric layer increasing, the topography of as-irradiated Ag-based thin films became smoother while the as-annealed Ag-based thin films had a rougher surface. LSPR absorption of both ITO/Ag and TiO2/Ag bilayers showed red shift with the thickness of dielectric layer increasing. The electromagnetic field coupling between dielectric layers and Ag thin films contributed to increase significantly the sensitivity of surface enhanced Raman scattering (SERS). Additionally, the result of finite-difference time-domain (FDTD) simulation was in good agreement with that of the experiment.

Influence of dielectric environment on exciton and bi-exciton properties in colloidal, type II quantum dots

We present theoretical calculations of type II CdSe/CdTe quantum dots systems. We use an 8-band k.p Hamiltonian that includes spin-orbit interaction, strain, and first order piezoelectric effects. Exciton and bi-exciton states are found using the configuration interaction (CI) method that explicitly includes the effects of the Coulomb interaction, as well as exchange and correlation effects between many-electron configurations. We study convergence of the CI Hamiltonian with respect to the number of single particle states used in creation of the Hamiltonian. We show that there is a very strong correlation between the dielectric constant of the environment and exciton and bi-exciton energies.

Influence of dielectric environment on the role of spin–orbit interaction for image potentials

We present a formalism for calculating the image potential for a two‐dimensional electron gas (2DEG) with Rashba spin–orbit interaction (SOI) as well as for a 2D topological insulator (TI). The formalism is further generalized for including the Coulomb coupled multiple layers. Roles of broken inversion symmetry near the surface and the dielectric environment are investigated by using a surface‐response function. The insignificant role of SOI in 2DEG is dramatically enhanced in TI by selecting a small relative permittivity for the dielectric environment. Manipulating is proven to provide an efficient way to drive electrons with opposite spins into two different integral quantum Hall states. The prediction made in this paper is expected to be experimentally observable for a 2DTI system, such as Bi2 Se3, with a helical spin behavior and a dominant linear Rashba SOI‐like term in the energy dispersion.

Influence of dielectric environment on screening of electron-phonon interaction in quantum well structures

In this Brief Report, we show that low-temperature transport parameters of quantum well structures are influenced essentially by the properties of the dielectric environment. In particular, if the quantum well is placed in the vicinity of a conductive region, screening of the electron-small wave vector phonon interaction becomes independent on the wave vector, which changes the temperature dependence of the transport parameters. This fact is often neglected under the analysis of experimental measurements. For illustration, we calculate the temperature dependence of the energy loss rate and phonon-drag thermopower for $\mathrm{Si}\mathrm{Ge}∕\mathrm{Si}$ quantum wells, which under the Bloch-Gr\"uneisen regime are proportional to some power of temperature. The results of calculations show crossover in the exponent of this dependence, whose position depends on the distance between the quantum well and the gate.