Spin polarization of two-dimensional electrons in different fractional states and around filling factor {nu}=1
Spin polarization of two-dimensional electrons in different fractional states and around filling factor {nu}=1
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不同分数态且填充因子{nu}=1附近二维电子的自旋极化
DOI：
10.1103/physrevb.55.10607
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发表时间：
1997
影响因子：
3.7
通讯作者：
K. Eberl
中科院分区：
文献类型：
--
作者：
I. Kukushkin;K. Klitzing;K. Eberl
通过对时间分辨发光的圆偏振的分析，研究了不同分数量子霍尔效应 (FQHE) 态的二维电子系统基态的自旋构型。该方法清楚地区分了完全自旋极化、部分自旋极化和自旋非极化 FQHE 基态。我们证明了在低磁场下自旋非极化或部分极化的 FQHE 态在高磁场下变成完全自旋极化。自旋极化的温度依赖性揭示了 {nu}=(2)/(3) 处的非单调行为。在 B{gt}4 T 和 {nu}{le}1 处，电子系统被发现是完全自旋极化的。该结果并不表明在高磁场极限下存在任何斯格明子激发。然而，在 B{lt}2 T 处，对于较低磁场，在 {nu}=(2)/(3) 和 (4)/(3) 处观察到的电子系统自旋去极化变得更宽，因此全自旋极化仅保留在 {nu}=1 周围的小范围内。这种行为可以被认为是斯格明子去极化的前兆，它将在塞曼能量和库仑能量之间较小的比率中占主导地位。 {版权} {ital 1997} {ital 美国物理学会}
The spin configuration of the ground state of a two-dimensional electron system is investigated for different fractional quantum Hall effect (FQHE) states from an analysis of circular polarization of time-resolved luminescence. The method clearly distinguishes between fully spin-polarized, partially spin-polarized, and spin-unpolarized FQHE ground states. We demonstrate that FQHE states which are spin unpolarized or partially polarized at low magnetic fields become fully spin polarized at high fields. Temperature dependence of the spin polarization reveals a nonmonotonic behavior at {nu}=(2)/(3). At B{gt}4 T and {nu}{le}1 the electron system is found to be fully spin polarized. This result does not indicate the existence of any Skyrmionic excitations in the high-magnetic-field limit. However, at B{lt}2 T the observed spin depolarization of the electron system at {nu}=(2)/(3) and (4)/(3) becomes broader for lower magnetic fields, so that full spin polarization remains only in a small vicinity around {nu}=1. Such a behavior could be considered as a precursor of Skyrmionic depolarization, which would dominate for smaller ratios between Zeeman and Coulomb energies. {copyright} {ital 1997} {ital The American Physical Society}