Numerical simulation of antiferromagnetic spin-pairing effects in diluted magnetic semiconductors and enhanced paramagnetism at interfaces

Fatah, J. M.; Piorek, T.; Harrison, P.; Stirner, T.; Hagston, W. E.

doi:10.1103/physrevb.49.10341

Cited by 77 publications

(31 citation statements)

References 7 publications

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“…However, the mean magnetisation gradually reduces with the increase in Mn contents in the crystal bulk due to the antiferromagnetic pairing of the nearest Mn neighbours giving rise to the spin-glass phase [15]. Nevertheless, the antiferromagnetically non-paired Mn 2+ concentration at surface is suggested to be higher than in the bulk [16,17]. The possibility of alloy transformation to the ferromagnetic CdMnTe 2 compound opens when approaching to x = 0.5 [18].…”

Section: Introductionmentioning

confidence: 99%

Luminescence of Cd0.7Mn0.3Te Crystals in Transverse Magnetic Field

et al. 2006

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Photoluminescence of cleaved Cd 0.7 Mn 0.3 Te crystals is studied at T ≈ 1.6 K at the normal-and oblique (45 • ) incidence of the pumping Ar laser beam (λ = 488 nm) in magnetic fields −7 ≤ B ≤ 7 T in the Voigt geometry. At B = 0, photoluminescence maximum is found at 2.0819 eV at normal incidence (and backward emission) whereas the oblique incidence and emission shows photoluminescence maximum intensity at 2.0536 eV. The red shift of photoluminescence maximum position with the rise in B is observed and the results are found to be in good agreement with sp−d exchange interaction model for the oblique incidence case. Backward emitted photoluminescence line is found to narrow from 26.2 to 23.5 meV with the rise in B from 0 to 7 T. Alloy disorder contribution exhibits opposite trend to broaden, as is calculated on the basis of the matrix of the energy gap dependence on x and B. Therefore the observed photoluminescence line narrowing is assigned to the suppression of magnetic fluctuation in magnetic field. A linear size of magnetic fluctuation is estimated to be about 1/5 of the free exciton diameter. Photoluminescence maximum position difference in the normal-and oblique incidence cases is assigned to polaritons.

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Section: Introductionmentioning

confidence: 99%

Luminescence of Cd0.7Mn0.3Te Crystals in Transverse Magnetic Field

et al. 2006

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“…In the case of Zn Mn Se it is [18], [19] eV so the -potential is given by meV (24) As the barrier thickness decreases, interactions among the wells become stronger so the splitting becomes larger. Additionally, the spin splitting is increased because the antiferromagnetic interactions between magnetic ions are reduced which leads to significantly enhanced effective magnetic moments and thepotential [18], [19], [22], [23]. The thickness of magnetic barriers was here set to 1 nm, in the range considered in the literature [18], [19].…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

“…It takes into account the effect of graded interfaces, the interface roughness and the enhanced magnetization at interfaces. Since the parameters used for the characterization of the interface profile are not known for ZnMnSe-ZnCdSe-ZnSe systems, we used a modified model [22], [23] that introduces a 2-monolayer-wide intermixing region left and right of the DMS barrier assuming different Mn concentrations, effective Mn concentrations and effective temperatures in the barriers and the intermixing regions. The complete potential profile of a triple quantum-well structure including the intermixing regions represented by dashed lines is shown in Fig.…”

Section: Theoretical Modelmentioning

confidence: 99%

Dilute magnetic semiconductor quantum-well structures for magnetic field tunable far-infrared/terahertz absorption

Savić

Milanović

Ikonić

et al. 2004

IEEE J. Quantum Electron.

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Article:Savic, I., Milanovic, V., Ikonic, Z. et Abstract-The design of ZnCdSe-ZnMnSe-based quantum wells is considered, in order to obtain a large shift of the peak absorption wavelength in the far infrared range, due to a giant Zeeman splitting with magnetic field, while maintaining a reasonably large value of peak absorption. A triple quantum-well structure with a suitable choice of parameters has been found to satisfy such requirements. A maximal tuning range between 14.6 and 34.7 meV is obtained, when the magnetic field varies from zero to 5 T, so the wavelength of the absorbed radiation decreases from 85.2 to 35.7 m with absorption up to 1.25% at low temperatures. These structures might form the basis for magnetic field tunable photodetectors and quantum cascade lasers in the terahertz range.Index Terms-Infrared detectors, manganese alloys, magnetic field effects, quantum wells, quantum theory, tunable circuits and devices.

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“…In recent years, heterostructures such as multiple quantum wells (MQWs) containing DMS materials have been grown very sucessfully by several groups. Progress has been made in the understanding of the properties of Mn at the heterointerfaces [3,4]. It is now possible to use this knowledge to make detailed studies, by magnetic field experiments, of aspects of epitaxial growth such as asymmetric interfaces [5] and donor distributions in MQW samples [6], demonstrating that DMS systems are ideal model systems for the study of semiconductor heterostructures.…”

Section: Introductionmentioning

confidence: 99%

Comparison of multiple-quantum wells and quantum dots by below-bandgap photomodulated reflectivity

Klar

Wolverson

Ashenford

et al. 1996

Semicond. Sci. Technol.

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Large-area high density patterns of quantum dots with a diameter of 200 nm have been prepared from a series of four Zn0.93Mn0.07Te/ZnTe multiple quantum well structures of different well width (40Å, 60Å, 80Å and 100Å) by electron beam lithography followed by Ar + -ion beam etching. Below-bandgap photomodulated reflectivity spectra of the quantum dot samples and the parent heterostructures were then recorded at 10 K and the spectra were fitted to extract the linewidths and the energy positions of the excitonic transitions in each sample. The fitted results are compared to calculations of the transition energies in which the different strain states in the samples are taken into account. We show that the main effect of the nanofabrication process is a change in the strain state of the quantum dot samples compared to the parent heterostructures. The quantum dot pillars turn out to be freestanding, whereas the heterostructures are in a good approximation strained to the ZnTe lattice constant. The lateral size of the dots is such that extra confinement effects are not expected or observed.

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Numerical simulation of antiferromagnetic spin-pairing effects in diluted magnetic semiconductors and enhanced paramagnetism at interfaces

Cited by 77 publications

References 7 publications

Luminescence of Cd0.7Mn0.3Te Crystals in Transverse Magnetic Field

Luminescence of Cd0.7Mn0.3Te Crystals in Transverse Magnetic Field

Dilute magnetic semiconductor quantum-well structures for magnetic field tunable far-infrared/terahertz absorption

Comparison of multiple-quantum wells and quantum dots by below-bandgap photomodulated reflectivity

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