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Takeyama, S.; Adachi, S.; Takagi, Yoshihiro; Aguekian, V.F.

doi:10.1103/physrevb.51.4858

Cited by 42 publications

(33 citation statements)

References 24 publications

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“…Thus the FWHM broadening for x = 0.3 due to composition disorder tends to be 13.9 meV. As the calculated value of band-gap energy standard deviation σ E ≈ 6 meV characterizes the fluctuations of random potential profile in the compound, this fact strongly supports the idea of excitons localized by disorder fluctuations in A II 1−x Mn x B VI compounds with higher Mn mole fraction [12][13][14]. Several other authors [15,16] arrive at the same relation for disorder-induced FWHM value, though using different probability expressions to describe the composition fluctuations of the compound from the mean value.…”

Section: Luminescence Line Analysissupporting

confidence: 65%

Luminescence of Cd_0.7Mn_0.3Te crystals in magnetic field: Linewidth, Landau quantization, and carrier effective mass

Barauskaitė¹,

Brazis²,

Ivanov³

et al. 2009

Lithuanian J. Phys.

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Cd0.7Mn0.3Te crystal photoluminescence is studied in magnetic field up to 7 T in Voigt geometry at 1.6-1.7 K temperature. The range of magnetic field where the approximation of effective band gap narrowing by the s, p − d exchange-interactioninduced term correctly describes experimental results is discussed. Luminescence linewidth (FWHM) broadening due to composition disorder and magnetization fluctuations is evaluated. Functional dependence on magnetic field of magnetic part in broadening, the FWHM(B)magn., is determined. From the patterns of Landau quantization in luminescence spectra the carrier effective mass value m * e = 0.104 is calculated and its increase in magnetic field is obtained. Contribution of nonparabolicity and band coupling effects is evaluated in the observed carrier effective mass growth effect.

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Section: Luminescence Line Analysissupporting

confidence: 65%

Luminescence of Cd_0.7Mn_0.3Te crystals in magnetic field: Linewidth, Landau quantization, and carrier effective mass

Barauskaitė¹,

Brazis²,

Ivanov³

et al. 2009

Lithuanian J. Phys.

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“…At low temperature, the presence of the EMP bound to a neutral acceptor, which was termed as a bound magnetic polaron (BMP), was reported [2]. In addition, when the Mn concentration increases, an alloy potential fluctuation (APF) produced by an inhomogeneous spatial distribution of Mn ions localizes an exciton, so that the localized exciton magnetic polaron (LMP) comes to play an important role regarding optical properties, particularly in luminescent processes [2][3][4][5][6][7][8]. At low Mn concentration, the photoluminescence (PL) of the EMP bound to neutral accepters was observed [2,3,6,8].…”

Section: Introductionmentioning

confidence: 97%

“…In addition, when the Mn concentration increases, an alloy potential fluctuation (APF) produced by an inhomogeneous spatial distribution of Mn ions localizes an exciton, so that the localized exciton magnetic polaron (LMP) comes to play an important role regarding optical properties, particularly in luminescent processes [2][3][4][5][6][7][8]. At low Mn concentration, the photoluminescence (PL) of the EMP bound to neutral accepters was observed [2,3,6,8]. By increasing the Mn concentration, the LMP became dominant in the PL spectrum [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Propagation effect on photoluminescence of spin-aligned high-density exciton magnetic polarons in Cd 0.8 Mn 0.2 Te

Nagata

Hirase

Miyajima

2017

Journal of Luminescence

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“…In turn, these aligned local moments act back on the exciton's spin, which lowers the exciton's energy, further localizes the exciton, and further stabilizes the polaron. The stability and binding energy of EMPs therefore depends on the detailed interplay between many factors including the exciton lifetime, the polaron formation time, the exchange field B ex , sample dimensionality, and temperature.EMPs and collective magnetic phenomena have been experimentally studied in a variety of Mn 2+ -doped semiconductor nanostructures, including CdMnSe and CdMnTe-based epilayers and quantum wells [34][35][36][37][38][39][40][41][42], selfassembled CdMnSe and CdMnTe quantum dots grown by molecular-beam epitaxy [14][15][16][18][19][20][21][22][23][24][25], and most recently in CdMnSe nanocrystals synthesized via colloidal techniques [8,28]. Common measurement techniques include the analysis of conventional (i.e., non-resonant) PL [8, 14, 15,18,21,28,39] and time-resolved PL [8, 16,28,34,35,40].…”

mentioning

confidence: 99%

“…Common measurement techniques include the analysis of conventional (i.e., non-resonant) PL [8, 14, 15,18,21,28,39] and time-resolved PL [8, 16,28,34,35,40].…”

mentioning

confidence: 99%

Direct Measurements of Magnetic Polarons in Cd_1–xMn_xSe Nanocrystals from Resonant Photoluminescence

et al. 2017

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In semiconductors, quantum confinement can greatly enhance the interaction between band carriers (electrons and holes) and dopant atoms. One manifestation of this enhancement is the increased stability of exciton magnetic polarons in magnetically-doped nanostructures. In the limit of very strong 0D confinement that is realized in colloidal semiconductor nanocrystals, a single exciton can exert an effective exchange field Bex on the embedded magnetic dopants that exceeds several tesla. Here we use the very sensitive method of resonant photoluminescence (PL) to directly measure the presence and properties of exciton magnetic polarons in colloidal Cd1−xMnxSe nanocrystals. Despite small Mn 2+ concentrations (x=0.4-1.6%), large polaron binding energies up to ∼26 meV are observed at low temperatures via the substantial Stokes shift between the pump laser and the resonant PL maximum, indicating nearly complete alignment of all Mn 2+ spins by Bex. Temperature and magnetic field-dependent studies reveal that Bex ≈ 10 T in these nanocrystals, in good agreement with theoretical estimates. Further, the emission linewidths provide direct insight into the statistical fluctuations of the Mn 2+ spins. These resonant PL studies provide detailed insight into collective magnetic phenomena, especially in lightly-doped nanocrystals where conventional techniques such as nonresonant PL or time-resolved PL provide ambiguous results.Advances in the colloidal synthesis of magneticallydoped nanomaterials have sparked a renewed focus on low-dimensional magnetic semiconductors [1][2][3][4][5][6][7][8]. The interesting magnetic properties of these materials originates in the strong sp-d exchange interactions that exist between carrier spins (i.e., band electrons and holes with s-and p-type wavefunctions) and the local 3d spins of embedded paramagnetic dopant atoms such as Mn, Co,. At the microscopic level, the strength of this interaction for a dopant located at position r i scales with the probability density of the carrier envelope wavefunctions at that point: |ψ e,h (r i )| 2 . As such, local spin-spin interactions can be greatly enhanced by strong quantum confinement, which compresses carrier wavefunctions to nanometer-scale volumes and therefore increases |ψ e,h (r)| 2 . The extent to which these exchange interactions can be enhanced and controlled via quantum confinement is an area of significant current interest and has recently been studied in a variety of magnetically-doped semiconductor nanostructures, including nanoribbons [12, 13], nanoplatelets [14], epitaxial quantum dots [14][15][16][18][19][20][21][22][23][24][25][26], and colloidal nanocrystals [1-8, 27, 28, 30].A particularly striking consequence of sp-d interactions in II-VI semiconductors is the formation of exciton magnetic polarons (EMPs), wherein the effective magnetic exchange field from a single photogenerated exciton -B ex -induces the collective and spontaneous ferromagnetic alignment of the magnetic dopants within its wavefunction envelope, generating a net local...

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Exciton localization by magnetic polarons and alloy fluctuations in the diluted magnetic semiconductorCd1−x

Cited by 42 publications

References 24 publications

Luminescence of Cd_0.7Mn_0.3Te crystals in magnetic field: Linewidth, Landau quantization, and carrier effective mass

Luminescence of Cd_0.7Mn_0.3Te crystals in magnetic field: Linewidth, Landau quantization, and carrier effective mass

Propagation effect on photoluminescence of spin-aligned high-density exciton magnetic polarons in Cd 0.8 Mn 0.2 Te

Direct Measurements of Magnetic Polarons in Cd_1–xMn_xSe Nanocrystals from Resonant Photoluminescence

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Exciton localization by magnetic polarons and alloy fluctuations in the diluted magnetic semiconductorCd1−x

Cited by 42 publications

References 24 publications

Luminescence of Cd0.7Mn0.3Te crystals in magnetic field: Linewidth, Landau quantization, and carrier effective mass

Luminescence of Cd0.7Mn0.3Te crystals in magnetic field: Linewidth, Landau quantization, and carrier effective mass

Propagation effect on photoluminescence of spin-aligned high-density exciton magnetic polarons in Cd 0.8 Mn 0.2 Te

Direct Measurements of Magnetic Polarons in Cd1–xMnxSe Nanocrystals from Resonant Photoluminescence

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Product

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Luminescence of Cd_0.7Mn_0.3Te crystals in magnetic field: Linewidth, Landau quantization, and carrier effective mass

Luminescence of Cd_0.7Mn_0.3Te crystals in magnetic field: Linewidth, Landau quantization, and carrier effective mass

Direct Measurements of Magnetic Polarons in Cd_1–xMn_xSe Nanocrystals from Resonant Photoluminescence