Ferromagnetic transition in diluted magnetic semiconductors

• Дата: 1999
• Автор: Dietl, T.
• Формат: Стаття
• Мова: English
• Опубліковано: Інститут фізики конденсованих систем НАН України 1999
• Назва видання: Condensed Matter Physics
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/120538
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: Ferromagnetic transition in diluted magnetic semiconductors / T. Dietl // Condensed Matter Physics. — 1999. — Т. 2, № 3(19). — С. 495-508. — Бібліогр.: 50 назв. — англ.

A summary is given of recent theoretical works on effects of the Ruderman- Kittel-Kasuya-Yosida (RKKY) interaction between the localized spins in various dimensionality systems of doped diluted magnetic semiconductors (DMS). Since this interaction is long-range, its influence on the temperature and magnetic field dependencies of magnetization and spin splitting of the bands is evaluated in the mean field approximation, but by taking into consideration disorder-modified carrier-carrier interactions. Theoretical evaluations show that the hole densities, which can presently be achieved, are sufficiently high to drive a paramagnetic- ferromagnetic phase transition in bulk and modulation-doped structures of II-VI DMS. The results of recent magnetooptical studies on MBE-grown samples, containing a single, modulation-doped, 8 nm quantum well of Cd₁₋xMnxTe/Cd₁₋y₋zMgyZnzTe:N are shown to corroborate the theoretical expectations. These studies reveal the presence of a ferromagnetic transition induced by the two-dimensional hole gas. The transition occurs between 1.8 and 2.5 K, depending on the Mn concentration x, in agreement with the theoretical model.