Spin interactions in diluted magnetic semiconductors and magnetic semiconductor structures

Abstract

The spin-dependent interactions in diluted magnetic semiconductors are reviewed. The non-trivial dependence of the p-d and the d-d exchange interactions, which rule the magnetic properties of these materials, on the electronic configuration of the magnetic ions is presented. Depending on the occupation numbers in the ionic d shell and the position of the d level with respect to the bands, both the kinetic exchange and the superexchange can lead to antiferromagnetic, ferromagnetic Kondo-like interactions or even orbital dependent, sensitive to Jahn-Teller distortion couplings. Finally, the interactions explaining the ferromagnetism in III-V and p-II-VI with Mn ions, the magnetic properties in semiconductor quantum wells and the interlayer spin correlations in magnetic/non-magnetic semiconductor superlattices are discussed.

Orbital pathways for Mn2+-carriersp−dexchange in diluted magnetic semiconductor quantum dots

“…Most analyses of dopant-carrier magnetic exchange in quantum-confined DMSs have relied on methods developed to describe the corresponding bulk materials. [1][2][3][32][33][34][35][36] Whereas the general features of sp-d exchange appear to translate across length scales, specific contrasts have been emphasized in some cases. 12,13,[36][37][38][39][40] Most prominently, a strong quantum-confinement-induced change in the fundamental nature of the conduction-band-electron ( e CB − ) -Mn 2+ exchange (s-d exchange) interaction has been described both theoretically 36,37 and experimentally.…”

EPR Spectra of Cr in CdTe Crystals

“…Diluted magnetic semiconductors are advanced materials for magneto--electronics due to the possibility of the control of magnetic properties by modulation of the carrier density [1][2][3]. Cr-based diluted magnetic semiconductors are also promising materials for new optoelectronic devices e.g.…”

“…tunable mid-infrared lasers (CdSe:Cr, ZnSe:Cr, CdMnTe:Cr [4]), converters of red-green into blue light [5]. The observed ferromagnetic p−d exchange interactions in zinc chalcogenides recommends them as the material for spintronics as well [2,6,7]. EPR investigations of the chromium in these crystals reveals this dopant in Cr 2+ state [8,9].…”

Ferromagnetic Semiconductors

“…However, shallow acceptors will produce band holes only if the d N +1 /d N donor level resides at lower energies, that is in the valence band. Furthermore, except for some resonant situations, the magnitudes of |βN 0 | are small for N < 5 because of opposite signs of two relevant contributions [141]. With these arguments in mind, (Ga,Fe)N and (Ga,Co)N co-doped with acceptor impurities appear as promising materials [43,68].…”