HoleCr+ nanomagnet in a semiconductor quantum dot

We study a diluted magnetic semiconductor system based on the spin of the ionized acceptor Cr+. We show that the negatively charged Cr+ ion, an excited state of the Cr in II-VI semiconductor, can be stable when inserted in a CdTe quantum dot (QD). The Cr+ attracts a heavy hole in the QD and form a s...

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Bibliographic Details
Published in:Physical review. B 2021-07, Vol.104 (4), p.1
Main Authors: Tiwari, V, Arino, M, Gupta, S, Morita, M, Inoue, T, Caliste, D, Pochet, P, Boukari, H, Kuroda, S, Besombes, L
Format: Article
Language:English
Subjects:
Cadmium tellurides
Electrons
Ferromagnetism
Ground state
II-VI semiconductors
Low temperature
Magnetic semiconductors
Optical pumping
Quantum dots
Relaxation time
Thermalization (energy absorption)
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Summary:We study a diluted magnetic semiconductor system based on the spin of the ionized acceptor Cr+. We show that the negatively charged Cr+ ion, an excited state of the Cr in II-VI semiconductor, can be stable when inserted in a CdTe quantum dot (QD). The Cr+ attracts a heavy hole in the QD and form a stable hole-Cr+ complex. Optical probing of this system reveals a ferromagnetic coupling between heavy holes and Cr+ spins. At low temperature, the thermalization on the ground state of the hole-Cr+ system with parallel spins prevents the optical recombination of the excess electron on the 3d shell of the atom. We study the dynamics of the nanomagnet formed by the hole-Cr+ exchange interaction. The ferromagnetic ground states with Mz = ± 4 can be controlled by resonant optical pumping and a spin relaxation time in the 20 μs range is obtained at T = 4.2 K. This spin memory at zero magnetic field is limited by the interaction with phonons.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.104.L041301