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Influence of nonmagnetic impurity scattering on spin dynamics in diluted magnetic semiconductors

Title data

Cygorek, Moritz ; Ungar, Florian ; Tamborenea, Pablo I. ; Axt, Vollrath M.:
Influence of nonmagnetic impurity scattering on spin dynamics in diluted magnetic semiconductors.
In: Physical Review B. Vol. 95 (2017) Issue 4 . - Art.Nr. 045204, 15 S..
ISSN 0163-1829
DOI: https://doi.org/10.1103/PhysRevB.95.045204

Project information

Project financing: Supported by the Universidad de Buenos Aires, project UBACyT 2014-2017 No. 20020130100514BA and, from CONICET, project PIP 11220110100091.

Abstract in another language

The doping of semiconductors with magnetic impurities gives rise not only to a spin-spin interaction between quasifree carriers and magnetic impurities but also to a local spin-independent disorder potential for the carriers. Based on a quantum kinetic theory for the carrier and impurity density matrices as well as the magnetic and nonmagnetic carrier-impurity correlations, the influence of the nonmagnetic scattering potential on the spin dynamics in DMS after optical excitation with circularly polarized light is investigated using the example of Mn-doped CdTe. It is shown that non-Markovian effects, which are predicted in calculations where only the magnetic carrier-impurity interaction is accounted for, can be strongly suppressed in the presence of nonmagnetic impurity scattering. This effect can be traced back to a significant redistribution of carriers in k-space which is enabled by the build-up of large carrier-impurity correlation energies. A comparison with the Markov limit of the quantum kinetic theory shows that, in the presence of an external magnetic field parallel to the initial carrier polarization, the asymptotic value of the spin polarization at long times is significantly different in the quantum kinetic and the Markovian calculations. This effect can also be attributed to the formation of strong correlations, which invalidates the semiclassical Markovian picture and it is stronger when the nonmagnetic carrier-impurity interaction is accounted for. In an external magnetic field perpendicular to the initial carrier spin, the correlations are also responsible for a renormalization of the carrier spin precession frequency. Considering only the magnetic carrier-impurity interaction, a significant renormalization is predicted for a very limited set of material parameters and excitation conditions. Accounting also for the nonmagnetic interaction, a relevant renormalization of the precession frequency is found to be more ubiquitous.

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
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: 06 Nov 2017 12:40
Last Modified: 30 Oct 2019 09:17
URI: https://eref.uni-bayreuth.de/id/eprint/40300