English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

The main problem in theoretical analysis of structures with strongconfinement is the fact that standard mathematical tools: differentialequations and Fourier's transformations are no longer applicable. In this paperwe have demonstrated that method of Green's functions can be successfully usedon low-dimension crystal samples, as a consequence of quantum size effects. Wecan illustrate modified model through the prime cubic structure molecularcrystal: bulk and ultrathin film. Our analysis starts with standard excitonHamiltonian with definition of commutative Green's function and equation ofmotion. We have presented detailed procedure of calculations of Green'sfunctions, and further dispersion law, distribution of states and relativepermittivity for bulk samples. After this, we have followed the same proceduresfor obtaining the properties of excitons in ultra-thin films. The results havebeen presented graphically. Besides modified method of Green's functions wehave shown that the exciton energy spectrum is discrete in film structures(with number of energy levels equal to the number of atomic planes of thefilm). Compared to the bulk structures, with continual absorption zone, in filmstructures exist resonant absorption peaks. With increased film thicknessdifferences between bulk and film vanish.

Exact Microtheoretical Approach to Calculation of Optical Properties of Ultralow Dimensional Crystals