Localized exciton magnetic polarons in Cd1-xMnxTe.
Localized exciton magnetic polarons in Cd1-xMnxTe.
复制标题
Cd1-xMnxTe 中的局域激子磁极化子。
DOI：
10.1103/physrevb.49.10248
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
E. Göbel
中科院分区：
文献类型：
--
作者：
G. Mackh;W. Ossau;D. Yakovlev;A. Waag;G. Landwehr;R. Hellmann;E. Göbel
Using the method of selective excitation of the exciton luminescence in ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Mn}}_{\mathit{x}}$Te epilayers we have measured energies of localized magnetic polarons (LMP's) for alloys with manganese mole fractions x\ensuremath{\le}0.34. The suppression of the LMP energy has been studied in external magnetic fields and with temperature increase. Polaron formation times and exciton lifetimes have been measured by time-resolved photoluminescence. We have found that in alloys with x0.17 the polaron formation process is interrupted by exciton recombination and, as a result, the LMP does not reach its equilibrium energy. This dynamical effect on the polaron energy together with the strong sensitivity of the LMP formation to the conditions of primary exciton localization causes the absence of the LMP formation in layers with x0.1. Antiferromagnetic clustering of Mn ions, which leads to the spin-glass phase formation at low temperatures, affects the polaron energy and results in the increasing stability of LMP's against suppression by temperature increase and magnetic fields. In ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Mn}}_{\mathit{x}}$Te with xg0.20 a considerable part of the polaron energy is controlled by the input of clusters of antiferromagnetically coupled Mn spins located in the nonuniform molecular field of localized excitons. The comparison of the exciton Zeeman splitting and the LMP magnetic-field suppression provides insight into the internal structure of LMP's.
Using the method of selective excitation of the exciton luminescence in ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Mn}}_{\mathit{x}}$Te epilayers we have measured energies of localized magnetic polarons (LMP's) for alloys with manganese mole fractions x\ensuremath{\le}0.34. The suppression of the LMP energy has been studied in external magnetic fields and with temperature increase. Polaron formation times and exciton lifetimes have been measured by time-resolved photoluminescence. We have found that in alloys with x0.17 the polaron formation process is interrupted by exciton recombination and, as a result, the LMP does not reach its equilibrium energy. This dynamical effect on the polaron energy together with the strong sensitivity of the LMP formation to the conditions of primary exciton localization causes the absence of the LMP formation in layers with x0.1. Antiferromagnetic clustering of Mn ions, which leads to the spin-glass phase formation at low temperatures, affects the polaron energy and results in the increasing stability of LMP's against suppression by temperature increase and magnetic fields. In ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Mn}}_{\mathit{x}}$Te with xg0.20 a considerable part of the polaron energy is controlled by the input of clusters of antiferromagnetically coupled Mn spins located in the nonuniform molecular field of localized excitons. The comparison of the exciton Zeeman splitting and the LMP magnetic-field suppression provides insight into the internal structure of LMP's.