Ultrafast magnetic polaron dynamics in Cd1-xMnxTe/ZnTe multiple quantum wells

Citation
R. Pittini et al., Ultrafast magnetic polaron dynamics in Cd1-xMnxTe/ZnTe multiple quantum wells, PHYSICA E, 10(1-3), 2001, pp. 326-330
Citations number
5
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICA E
ISSN journal
1386-9477 → ACNP
Volume
10
Issue
1-3
Year of publication
2001
Pages
326 - 330
Database
ISI
SICI code
1386-9477(200105)10:1-3<326:UMPDIC>2.0.ZU;2-D
Abstract
Optical pump-probe experiments were carried out in Cd1-xMnxTe/ZnTe multiple quantum wells to study the dynamics of the excitons and the exciton magnet ic polarons in these materials. In the pump-probe: spectra, three signals w ere detected. The main signal is negative and monitors the energy relaxatio n of the excitons created by the pump pulse. The two other pump-probe signa ls are positive and their intensity grows during the time when the excitons created by the pump pulse recombine. The low-energy positive pump-probe si gnal is found to track the average Mn spin polarization in the sample. Expe riments performed with circular polarization show that long-range order is induced by a sufficiently intense pump beam. But in our samples, the spins of the excitons are found to be oriented mainly antiparallel to the long-ra nge magnetization generated after the pump excitation. Furthermore, we foun d that, at high excitation densities, the excitons couple antiferromagnetic ally to the long-range 'background' magnetization of the Mn spins. (C) 2001 Published by Elsevier Science B.V.