From Magnetic Polarons to Ferromagnetism

• Authors: T. Dietl
• Languages of publication: EN

Abstracts

EN

A brief overview is given on selected effects of the exchange coupling between effective mass electrons and localized spins in II-VI semiconductors containing Mn ions. In the case of a carrier or exciton trapped by an impurity or defect, the exchange interaction leads to zero-field spin-splitting. The current theory of such complexes, known as bound magnetic polarons, describes correctly their spectroscopic and thermodynamic properties as well as their formation dynamics. At the same time, a free magnetic polaron - a delocalized carrier accompanied by a traveling cloud of polarized spins - is not expected to exist for the actual values of the coupling constants. However, hole scattering by thermodynamic and static fluctuations is shown to affect significantly its energy. For a strong coupling, the corresponding renormalization has to be described by a non-perturbative approach. Finally, the influence of the carrier liquid upon the Mn spins is discussed. Here, either optical pumping or p-type doping may lead to a ferromagnetic order, both in bulk and layered structures. Because of a long-range character of the carrier mediated interactions, this ordering is not destroyed by the fluctuations, even in the reduced dimensionality systems.

Keywords

EN

78.47.+p; 75.70.Cn; 78.55.Et; 78.66.Hf

Discipline

• 78.66.Hf: II-VI semiconductors
• 78.55.Et: II-VI semiconductors
• 75.70.Cn: Magnetic properties of interfaces (multilayers, superlattices, heterostructures)

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 1998
• Volume: 94
• Issue: 2
• Pages: 111-123

Dates

published

1998-08

Contributors

author

T. Dietl

• Institute of Physics, Polish Academy of Sciences and College of Science, Al. Lotników 32/46, 02-668 Warszawa, Poland

Identifiers

DOI

10.12693/APhysPolA.94.111