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Trend reversal in the magnetic-field dependence of exciton spin-transfer rates in diluted magnetic semiconductors due to non-Markovian dynamics

Title data

Ungar, Florian ; Cygorek, Moritz ; Axt, Vollrath M.:
Trend reversal in the magnetic-field dependence of exciton spin-transfer rates in diluted magnetic semiconductors due to non-Markovian dynamics.
In: Physical Review B. Vol. 97 (30 January 2018) . - 045210. - 15 Seiten.
ISSN 0163-1829
DOI: https://doi.org/10.1103/PhysRevB.97.045210

Official URL: Volltext

Project information

Project financing: Deutsche Forschungsgemeinschaft

Abstract in another language

We investigate theoretically the influence of an external magnetic field on the spin dynamics of excitons in diluted magnetic semiconductor quantum wells. To this end, we apply a quantum kinetic theory beyond the Markov approximation which reveals that non-Markovian effects can significantly influence the exciton spin dynamics. If the magnetic field is oriented parallel to the growth direction of the well, the Markovian spin-transfer rate decreases monotonically with increasing field as predicted by Fermi's golden rule. The quantum kinetic theory follows this result qualitatively but predicts pronounced quantitative differences in the spin-transfer rate as well as in the long-time spin polarization. However, for an in-plane magnetic field, where the Markovian spin-transfer rate first drops and then increases again, quantum kinetic effects become so pronounced that the Markovian trend is completely reversed. This is made evident by a distinct maximum of the rate followed by a monotonic decrease. The deviations can be traced back to a redistribution of carriers in energy space caused by correlations between excitons and magnetic dopants. The same effect leads to a finite electron-spin polarization at long times in longitudinal as well as transverse fields which is much larger than the corresponding Markovian prediction.

Further data

Item Type: Article in a journal
Refereed: Yes
Keywords: diluted magnetic semiconductors; DMS, spintronics; carrier-impurity correlations; carrier-dopant correlations; nonmagnetic scattering; spin transfer; exchange interaction; spin polarized carriers; quantum kintics; built-up of correlation energy; optical excitation; laser induced spin dynamics; ultrafast dynamics; nonlinear optics; exciton spin dynamics; dynamics controlled truncation
Subject classification: condensed matter physics (theoretical)
Institutions of the University: Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics
Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Theoretical Physics III > Chair Theoretical Physics III - Univ.-Prof. Dr. Martin Axt
Faculties
Faculties > Faculty of Mathematics, Physics und Computer Science
Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Theoretical Physics III
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 530 Physics
Date Deposited: 02 Feb 2018 06:38
Last Modified: 02 Feb 2018 06:38
URI: https://eref.uni-bayreuth.de/id/eprint/42179