Diluted Magnetic Semiconductors: Basic Physics and Optical Properties

Cibert, J.; Scalbert, D.

doi:10.1007/978-3-540-78820-1_13

Cited by 22 publications

(20 citation statements)

References 133 publications

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“…In contrast, the bottom of the conductance (Ba) spin-minority band (↓-band) is pushed down because of the hybridization with unoccupied Mn states. This provides the magnetic coupling between the local spin and itinerant carriers [37]. Another manifestation of the same effect, verifiable experimentally, is that with Mn doping the indirect gap between the top of the valence ↑-band and the bottom of the conduction ↓-band is reduced and eventually closes when the doping is large enough, see the inset of Fig.…”

Section: Introduction-supporting

confidence: 55%

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Theory of Mn-doped II-II-V semiconductors

2014

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A recently discovered magnetic semiconductor Ba1−xKx(Zn1−yMny)2As2, with its decoupled spin and charge doping, provides a unique opportunity to elucidate the microscopic origin of the magnetic interaction and ordering in dilute magnetic semiconductors (DMS). We show that (i) the conventional density functional theory (DFT) accurately describes this material, and (ii) the magnetic interaction emerges from the competition of the short-range superexchange and a longer-range interaction mediated by the itinerant As holes, coupled to Mn via the Schrieffer-Wolff p−d interaction representing an effective Hund's rule coupling, J eff H . The key difference between the classical double exchange and the actual interaction in DMS is that an effective J eff H , as opposed to the standard Hund's coupling JH , depends on the Mn d−band position with respect to the Fermi level, and thus allows tuning of the magnetic interactions. The physical picture revealed for this transparent system may also be applicable to more complicated DMS systems.Introduction-The carrier-mediated magnetism in DMS [1-5] offers a versatile control of the exchange interaction by tuning the Curie temperature T C through changes in the carrier density [5][6][7][8]. However, despite four decades of intensive work, challenges remain and materials complexity often hinders theoretical understanding. The origin of magnetic ordering [1-3, 5] and paths to higher T C remain strongly debated [3,9,10].

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Section: Introduction-supporting

confidence: 55%

“…This is formally the same as the Schrieffer-Wolff transformation frequently used for Kondo systems [11,37]. The DMS literature typically refers to this as the p − d model.…”

Section: Introduction-mentioning

confidence: 99%

Theory of Mn-doped II-II-V semiconductors

2014

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“…The rate of spin relaxation of isolated ions increases with the strength of the spin–orbit interaction405556, which depends on the magnetic ion and the host material57. Therefore it is reasonable to use QDs based on semiconductors with light anions: sulphides, oxides and nitrides, as they exhibit a weak spin–orbit interaction.…”

Section: Discussionmentioning

confidence: 99%

Designing quantum dots for solotronics

et al. 2014

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Solotronics, optoelectronics based on solitary dopants, is an emerging field of research and technology reaching the ultimate limit of miniaturization. It aims at exploiting quantum properties of individual ions or defects embedded in a semiconductor matrix. It has already been shown that optical control of a magnetic ion spin is feasible using the carriers confined in a quantum dot. However, a serious obstacle was the quenching of the exciton luminescence by magnetic impurities. Here we show, by photoluminescence studies on thus-far-unexplored individual CdTe dots with a single cobalt ion and CdSe dots with a single manganese ion, that even if energetically allowed, nonradiative exciton recombination through single-magnetic-ion intra-ionic transitions is negligible in such zero-dimensional structures. This opens solotronics for a wide range of as yet unconsidered systems. On the basis of results of our single-spin relaxation experiments and on the material trends, we identify optimal magnetic-ion quantum dot systems for implementation of a single-ion-based spin memory.

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“…Ds, 76.50.+g Diluted magnetic semiconductors (DMS) have recently been the subject of great interest [1,2] due to their potential in combining magnetic and semiconductor properties in a single material. The DMS are formed by replacing of cations in ordinary semiconductors with magnetic ions, typically Mn ions.…”

mentioning

confidence: 99%

“…The interplay of these interactions leads to a number of intriguing phenomena including tunable anticrossing of the modes and a field-induced change in a sign of the group velocity of the ion mode. Diluted magnetic semiconductors (DMS) have recently been the subject of great interest [1,2] due to their potential in combining magnetic and semiconductor properties in a single material. The DMS are formed by replacing of cations in ordinary semiconductors with magnetic ions, typically Mn ions.…”

mentioning

confidence: 99%

Spin waves in diluted magnetic quantum wells

2011

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We study collective spin excitations in two-dimensional diluted magnetic semiconductors, placed into external magnetic field. Two coupled modes of the spin waves (the electron and ion modes) are found to exist in the system along with a number of the ion spin excitations decoupled from the electron system. We calculate analytically the spectrum of the waves taking into account the exchange interaction of itinerant electrons both with each other and with electrons localized on the magnetic ions. The interplay of these interactions leads to a number of intriguing phenomena including tunable anticrossing of the modes and a field-induced change in a sign of the group velocity of the ion mode.PACS numbers: 75.30. Ds, 76.50.+g Diluted magnetic semiconductors (DMS) have recently been the subject of great interest [1,2] due to their potential in combining magnetic and semiconductor properties in a single material. The DMS are formed by replacing of cations in ordinary semiconductors with magnetic ions, typically Mn ions. Strong exchange interaction between the itinerant electrons and the electrons localized on d-shells of the magnetic ions leads to a number of remarkable features of the DMS. In particular, it results in the effective indirect interaction between the ion spins thus promising for creating room-temperature ferromagnetic systems that may offer advantages of semiconductors. It also dramatically enhances the effective coupling of the itinerant electrons with the external magnetic field. In contrast to conventional GaAs/GaAlAs systems, where small values of g−factor prevents manipulation of the spin degree of freedom, the giant electron Zeeman splitting arising in the DMS as a manifestation of the exchange interaction can be on the order of the Fermi energy [3,4], offering a wide range of spintronics applications.Here we discuss spin excitations in the twodimensional DMS. Our studies are motivated by recent experiments [5][6][7] and a theoretical discussion [7][8][9] focused on the spin dynamics in diluted magnetic Cd 1−x Mn x Te quantum wells placed into the magnetic field [10]. In Ref. 5, the spectrum of the spin waves, ω(k), was measured. Only one excitation mode was observed. It was demonstrated that the excitations exist in a finite range of wavelengths, k < k m , and their group velocity is negative: dω(k)/dk < 0. The experimental data were interpreted [5,8] in terms of conventional spin waves in the Fermi liquids [11], while k m was attributed to the edge of the Stoner continuum of the single-particle spin excitations. Such interpretation implies that the only effect of the magnetic ions on the electron spin waves is the strong renormalization of the electron Zeeman splitting. However, more recent experimental observations [6,7] supported by theoretical studies [7,9] appear to be in disagreement with this conclusion. Indeed, in Refs. [6,7] two modes of the collective homogeneous (k = 0) spin excitations were observed in Cd 1−x Mn x Te wells. The modes were identified [6,7,9] as the spin excitations o...

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Diluted Magnetic Semiconductors: Basic Physics and Optical Properties

Cited by 22 publications

References 133 publications

Theory of Mn-doped II-II-V semiconductors

Theory of Mn-doped II-II-V semiconductors

Designing quantum dots for solotronics

Spin waves in diluted magnetic quantum wells

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