A microscopic model for the dielectric function of Ge quantum wires

• Дата: 2005
• Автори: Alfaro, P., Vazquez, R., Lobota, I., Ramos, A.E., Cruz-Irisson, M.
• Формат: Стаття
• Мова: English
• Опубліковано: НТК «Інститут монокристалів» НАН України 2005
• Назва видання: Functional Materials
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/138882
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: A microscopic model for the dielectric function of Ge quantum wires / P. Alfaro, R. Vazquez, I. Lobota, A.E. Ramos, M. Cruz-Irisson // Functional Materials. — 2005. — Т. 12, № 4. — С. 680-684. — Бібліогр.: 14 назв. — англ.

Free-standing, infinitely long, and homogeneous quantum wires of square cross section are considered using the chessboard-like supercell model. The optical transition properties of Ge nanocrystals are studied by means of an sp³s* semiempirical tight-binding approximation. The calculations have been carried out for light polarized in the [100] direction, i.e., perpendicular to the wire alignment. Dependence of the imaginary part of the dielectric function on the quantum confinement is presented within two different schemes: intra-atomic and interatomic matrix elements, which are applied and compared. The principal results show that although the intra-atomic matrix elements are small in magni- tude, the interference between these terms and the interatomic matrix elements contrib- utes about 25 % of the total absorption. Thus, it appears that a quantitative treatment of nanostructures may not be possible (in general) without the inclusion of intra-atomic matrix elements.