Hole-
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 nanomagnet in a semiconductor quantum dot

Tiwari, Vivekanand; Arino, Masashi; Gupta, S.C.; Morita, Mariko; Inoue, T.; Caliste, Damien; Pochet, Pascal; Boukari, H.; Kuroda, Shinji; Besombes, L.

doi:10.1103/physrevb.104.l041301

Cited by 6 publications

(12 citation statements)

References 36 publications

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“…1 together with their low magnetic field dependence in a Faraday configuration. The emission of such dots at zero magnetic field consists in a minimum of 7 lines separated by a central gap ∆ [15]. Additional lower intensity lines can be observed in some of the dots (see QD1).…”

Section: Energy Levels In Positivelymentioning

confidence: 98%

“…The concentration of Cr was adjusted to obtain QDs containing 0, 1 or a few magnetic atoms. When doped with a single atom these dots permit to optically access the spin of a Cr 2+ ion [16] or, in the presence of a local background doping, to the spin of a hole-Cr + complex [15].…”

Section: Samples and Experimentsmentioning

confidence: 99%

“…Cr 2+ is the isoelectronic configuration of Cr in the II-VI semiconductor lattice. It has been demonstrated recently that the Cr in its Cr + oxidation state can also be stable and detected optically * lucien.besombes@neel.cnrs.fr when inserted in a CdTe QD [15]. The Cr + has an electronic configuration 3d 5 with a spin S=5/2 and no orbital momentum (L=0).…”

Section: Introductionmentioning

confidence: 99%

“…In optically active QDs, resonant photoluminescence (PL) and optical spin pumping are the most efficient tools to initialize and probe the dynamics of individual spins. It has been demonstrated that resonant optical pumping can be used to empty the low energy states of the hole-Cr + complex with a spin memory in the 20 µs range at low temperature [15]. The spin dynamics of hole-Cr + was found to depend on the conditions of optical excitation.…”

Section: Introductionmentioning

confidence: 99%

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Spin dynamics of positively charged excitons in Cr$^+$-doped quantum dots probed by resonant photoluminescence

Tiwari,

Inoue,

Kuroda

et al. 2022

Preprint

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We study the dynamics of the spin system that consist of a positively charged II-VI semiconductor quantum dot doped with a single Cr + ion. The resonant photoluminescence (PL) of the positively charged exciton coupled with the Cr + spin is used to analyze the main spin relaxation channels. The intensity of the resonant PL is reduced by an optical pumping of the spin of the resident hole-Cr + complex that can be seen as a nano-magnet. The spin memory can be partially erased by a non-resonant optical excitation. This leads to an increase of the resonant PL signal. The resonant PL is co-circularly polarized and corresponds to relaxation channels that conserve the Cr + spin |Sz|. The observation in the resonant-PL excitation spectra of optical transitions with a change of the Cr + spin permits to determine the magnetic anisotropy of the magnetic atom. Optical pumping, auto-correlation measurements and the power dependence of the PL intensity distribution show that the effective temperature of the hole-Cr + spin system is affected by the optical excitation through the local generation of phonons.

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Section: Energy Levels In Positivelymentioning

confidence: 98%

Section: Samples and Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Spin dynamics of positively charged excitons in Cr$^+$-doped quantum dots probed by resonant photoluminescence

Tiwari,

Inoue,

Kuroda

et al. 2022

Preprint

Self Cite

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“…Isolated spatially localized spins in semiconducting or insulating materials are promising quantum states for implementing information storage and processing technologies [1,2]. While current ultimate memory elements are still made of a huge number of spins or charges, reducing this number to unity or so has now became a reachable goal [3][4][5], leading to solotronic devices [6]. In addition, solid-state quantum computing and quantum metrology are also demanding for localized spin systems, embedded in a solid and robust insulating crystalline matrix [7,8].…”

Section: Introductionmentioning

confidence: 99%

Zero-field magnetic resonance of cobalt ion pairs in ZnO nanocrystals

Marin

Tiwari²,

Bertaina³

et al. 2022

Phys. Rev. B

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Cobalt-doped ZnO nanoparticles (NPs) with different Co concentrations are investigated by means of Xand Q-band electron spin resonance (ESR) near liquid-helium temperature in both parallel and perpendicular modes. The high crystal quality of the NPs allows for the hyperfine-structure resolution within the single Co 2+ ions' ESR powder spectra. Depending on cobalt concentration, common additional weak ESR lines are detected which are here demonstrated to arise from some Co 2+ high-spin pairs with a distance of about 4-6 Å. ESR simulations show that these 3/2 spin pairs are weakly coupled by an isotropic Heisenberg Hamiltonian with either ferromagnetic or antiferromagnetic J coupling constants, almost identical to those previously detected in bulk and microwire ZnO:Co. The presence of substantial (axial) single-ion anisotropy in ZnO:Co makes the different pairs' resonance positions strongly depending on the J value. For resonance frequency ν in the microwave range, four cobalt pairs can satisfy the condition |J| ∼ hν/3 to resonate at almost zero magnetic field. Such near-zero-field transitions notably resonate in the parallel ESR mode, which is the signature of the gapped nonlinear Zeeman effect, which is of particular interest for highly stable atomic-clock transitions.

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