Two dimensional exciton magnetic polaron in CdTe/Cd1−xMnxTe quantum well structures

Yakovlev, D. R.; Ossau, W.; Landwehr, G.; Bicknell-Tassius, R.N.; Waag, A.; Schmeusser, S.; Uraltsev, I. N.

doi:10.1016/0038-1098(92)90401-t

Cited by 57 publications

(18 citation statements)

References 15 publications

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“…For GaN thin film, the reported red shift of the energy band gap by increasing temperature to room temperature reaches about 61 meV [27]. The observed value of the red shift with increasing temperature in the present GaN MQW sample is smaller than that of pure GaN thin film by 19 meV.…”

Section: Temperature Dependence Of Photoluminescence Energycontrasting

confidence: 55%

Photoluminescence related to Gd3+:N-vacancy complex in GaN:Gd multi-quantum wells

Almokhtar

Emura

Koide

et al. 2015

Journal of Alloys and Compounds

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Section: Temperature Dependence Of Photoluminescence Energycontrasting

confidence: 55%

Photoluminescence related to Gd3+:N-vacancy complex in GaN:Gd multi-quantum wells

Almokhtar

Emura

Koide

et al. 2015

Journal of Alloys and Compounds

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“…In the semimagnetic semiconductors the Stokes shift of PL line is due to both po laron formation and exciton localization in nonmagnetic random potential, and it is necessary to distinguish between these two contributions. We use a method of selective excitation for the EMP studies in Cd 1-x Mnx Τe-based epilayers and heterostructures grown by molecular-beam epitaxy [20,22]. Excitons are excited selectively in the band of localized states at energies where the spectral diffusion due to phonon-assisted tunneling dues not occur during the exciton lifetime.…”

Section: Resultsmentioning

confidence: 99%

Magnetic Polaron Formation in Semimagnetic Semiconductor Heterostructures

Yakovlev

1996

Acta Phys. Pol. A

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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].…”

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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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Two dimensional exciton magnetic polaron in CdTe/Cd1−xMnxTe quantum well structures

Cited by 57 publications

References 15 publications

Photoluminescence related to Gd3+:N-vacancy complex in GaN:Gd multi-quantum wells

Photoluminescence related to Gd3+:N-vacancy complex in GaN:Gd multi-quantum wells

Magnetic Polaron Formation in Semimagnetic Semiconductor Heterostructures

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

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Two dimensional exciton magnetic polaron in CdTe/Cd1−xMnxTe quantum well structures

Cited by 57 publications

References 15 publications

Photoluminescence related to Gd3+:N-vacancy complex in GaN:Gd multi-quantum wells

Photoluminescence related to Gd3+:N-vacancy complex in GaN:Gd multi-quantum wells

Magnetic Polaron Formation in Semimagnetic Semiconductor Heterostructures

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

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