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arXiv 2107.03192cond-mat.mes-hallquant-ph
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半导体量子点中的空穴-Cr $^{+}$纳米磁体

A hole-Cr$^{+}$ nano-magnet in a semiconductor quantum dot

V. Tiwari, M. Arino, S. Gupta, M. Morita, T. Inoue, D. Caliste, P. Pochet, H. Boukari, S. Kuroda, L. Besombes

摘要:

我们研究了一种新的基于离子化受主Cr $^+$自旋的稀磁半导体系统。我们发现,带负电荷的Cr $^+$离子,在II-VI族半导体中的Cr的激发态,可以是稳定的,当插入到CdTe量子点(QD)。Cr $^+$吸引量子点中的重空穴并形成稳定的空穴-Cr $^+$复合物。该系统的光学探测揭示了重空穴和Cr $^+$自旋之间的铁磁耦合。在低温下,具有平行自旋的空穴-Cr $^+$系统基态的热化阻止了原子3 $d$壳层上多余电子的光学复合.我们研究了空穴-Cr $^+$交换相互作用形成的纳米磁体的动力学。用共振光抽运控制了$_z$ = $\pm$ 4的铁磁基态,在T=4.2 K时得到了20 $μ$ s范围内的自旋弛豫时间。这种在零磁场下的自旋记忆受到与声子相互作用的限制。

英文摘要:

We study a new 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 3$d$ shell of the atom. We study the dynamics of the nano-magnet formed by the hole-Cr$^+$ exchange interaction. The ferromagnetic ground states with M$_z$=$\pm$4 can be controlled by resonant optical pumping and a spin relaxation time in the 20 $μ$s range is obtained at T=4.2 K. This spin memory at zero magnetic field is limited by the interaction with phonons.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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