Theory of Electron Mediated Mn-Mn Interactions in Quantum Dots

Qu, Fanyao; Hawrylak, Paweł

doi:10.1103/physrevlett.96.157201

Cited by 71 publications

(67 citation statements)

References 25 publications

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“…25 I h,i (I e,i ) is the exchange integral of the hole (electron) with the Mn atom i, I eh the electron-hole exchange interaction and I n,n the short ranged antiferromagnetic Mn-Mn interaction. This latter coupling is only comparable with the carrier-Mn energy when the 2 Mn are positioned closed to each other (I Mn,Mn = 0.5 meV for neighboring atoms 17,18 ); it is neglected in the following calculations because the carrier-Mn interaction in the considered QD is very different for the two atoms, indicating that they are far apart.…”

Section: Model Hamiltonianmentioning

confidence: 99%

“…15,16 Thus, in a neutral dot containing 2 Mn atoms, the spins are only coupled via a very short range supercharge, which would be only relevant for first or second neighbors. 17,18 The injection of a single electron, whose wave function is spread along the entire dot, couples the 2 Mn and the electron spin ferromagnetically, resulting in a ground state with S = 11/2. This contrasts with the addition of a single exciton on the neutral dot, for which the Mn spins also couple ferromagnetically, but the strong spin-orbit coupling of the hole breaks spin rotational invariance.…”

Section: Introductionmentioning

confidence: 99%

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Optical control of the spin state of two Mn atoms in a quantum dot

et al. 2012

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We report on the optical spectroscopy of the spin of two magnetic atoms (Mn) embedded in an individual quantum dot interacting with a single electron, a single exciton, or a single trion. As a result of their interaction to a common entity, the Mn spins become correlated. The dynamics of this process is probed by time-resolved spectroscopy, which permits us to determine an optical orientation time in the range of a few tens of nanoseconds. In addition, we show that the energy of the collective spin states of the two Mn atoms can be tuned through the optical Stark effect induced by a resonant laser field.

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Section: Model Hamiltonianmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optical control of the spin state of two Mn atoms in a quantum dot

et al. 2012

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“…Recent theoretical 10,13,14,15 and experimental work 11 has focused either on a small number of electrons using the exact diagonalization approach at zero field (Refs. 14,15 ) for a 2D quantum dot or at nonzero field 13 including only the lowest single-particle states for a 3D system or the exciton states relevant for optical spectroscopy of self-assembled magnetic-doped quantum dots 10,11 . Here, we will examine thoroughly the exact properties of the system containing several correlated electrons and a single magnetic impurity in the presence of a magnetic field.…”

Section: Magnetic-doped Quantum Dotsmentioning

confidence: 99%

Magnetic field dependence of the many-electron states in a magnetic quantum dot: The ferromagnetic-antiferromagnetic transition

Nguyen

Peeters

2008

Phys. Rev. B

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The electron-electron correlations in a many-electron (Ne = 1, 2, ..., 5) quantum dot confined by a parabolic potential is investigated in the presence of a single magnetic ion and a perpendicular magnetic field. We obtained the energy spectrum and calculated the addition energy which exhibits cusps as function of the magnetic field. The vortex properties of the many-particle wave function of the ground state are studied and for large magnetic fields are related to composite fermions. The position of the impurity influences strongly the spin pair correlation function when the external field is large. In small applied magnetic field, the spin exchange energy together with the Zeeman terms leads to a ferromagnetic-antiferromagnetic(FM-AFM) transition. When the magnetic ion is shifted away from the center of the quantum dot a remarkable re-entrant AFM-FM-AFM transition is found as function of the strength of the Coulomb interaction. Thermodynamic quantities as the heat capacity, the magnetization, and the susceptibility are also studied. Cusps in the energy levels show up as peaks in the heat capacity and the susceptibility.

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“…Thus, in view of the above the RudermanKittelKasuyaYosida (RKKY) e−Mn interaction strength is proportional to the spin exchange matrix elements (for details see [5]): In the case of applied electric eld this expression changes tô…”

Section: Electric Eld Vs the Sp−d Couplingmentioning

confidence: 99%

Electron Mediated Mn-Mn Interaction in Quantum Dots

Ba̧k

2012

Acta Phys. Pol. A

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We present a theoretical study of magnetic interaction in quantum dots with magnetic Mn 2+ in dot impurities. We show that gate voltage applied to the quantum dot shifts the centers of electron clouds. Exact formulae for the perturbed spin density allow us to derive expression for the change of the strength of the sp−d coupling. Estimations show that sp−d exchange integral is very sensitive to the gate voltage variations. Exact formulae for the change of the eective exchange integrals are derived. As the spin coded qubits are elements of the RAM memory, a part of the energy stored in magnetic coupling will be dissipated when information is written or erased. We estimate this energy and nd it suciently large to destroy quantum coherence during quantum computing. Finally, we discuss the interdot spin coupling and show the eect of gate voltage operations on the spin intra-and interdot RudermanKittelKasuyaYosida coupling.

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Theory of Electron Mediated Mn-Mn Interactions in Quantum Dots

Cited by 71 publications

References 25 publications

Optical control of the spin state of two Mn atoms in a quantum dot

Optical control of the spin state of two Mn atoms in a quantum dot

Magnetic field dependence of the many-electron states in a magnetic quantum dot: The ferromagnetic-antiferromagnetic transition

Electron Mediated Mn-Mn Interaction in Quantum Dots

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