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Title: | Phonon Specificities and Thermodynamics of Crystalline Nanostructures Fononske specifičnosti i termodinamika kristalnih nanostruktura |
Authors: | Ilić Dušan | Keywords: | nanostructures, phonons, Green's functions, spectra, thermodynamics;nanostrukture, fononi, Grinove funkcije, spektri, termodinamika | Issue Date: | 23-Jan-2014 | Publisher: | Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu University of Novi Sad, Faculty of Sciences at Novi Sad |
Abstract: | <p>U disertacije je sprovedeno teorijsko istraživanje mikroskopskih i makroskopskih (termodinamičkih) osobina tankoslojnih i niskodimenzionih kristalnih struktura u okviru modela fonona akustičkog tipa. Upoređivanjem fononskih spektara i termodinamičkih svojstava u neograničenim i posmatranim nanostrukturama ustanovljeno je da se oni znatno razlikuju usled postojanja granica kod niskodimenzionih sistema. Takođe je primećeno da u fononskim spektrima niskodimenzionih struktura postoji energijski procep, što znači da je energija pobuđivanja fonona u niskodimenzionim kristalnim strukturama veća od one u balku. Ovo uzrokuje da toplotna kapacitivnost u niskotemperaturskoj oblasti ima i znatno niže vrednosti u ograničenim strukturama nego u masovnim uzorcima.</p> <p>In ths work, a theoretical study of microscopic and thermodynamic properties of thin-layered and low-dimensional crystalline structures of the model type of acoustic phonons was carried out. Comparison of the phonon spectra and thermodynamic properties of the infinite with the observed nanostructures revealed that they differ greatly because of the existence of borders in the low-dimensional systems. It is also noted that in the phonon spectra of nanostructures an energy gap exists, which means that the energy od excitation of phonons in the nanostructured crystal systems is higher than those of the bulk. This indicates that the heat capacitance in the low-temperature range ha a significantly lower values in bounded structures than in massive samples.</p> |
URI: | https://open.uns.ac.rs/handle/123456789/29419 |
Appears in Collections: | PMF Teze/Theses |
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