Groshaus J G, Plochocka-Polack P, Rappaport M, Umansky V, Bar-Joseph I, Dennis B S, Pfeiffer L N, West K W, Gallais Y, Pinczuk A
Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel and Bell Laboratories, Lucent Technology, Murray Hill, New Jersey 07974, USA.
Phys Rev Lett. 2007 Apr 13;98(15):156803. doi: 10.1103/PhysRevLett.98.156803. Epub 2007 Apr 12.
We present measurements of optical interband absorption in the fractional quantum Hall regime in a GaAs quantum well in the range 0<nu<or=1. We investigate the mechanism of singlet trion absorption, and show that its circular dichroism can be used as a probe of the spin polarization of the ground state of the two-dimensional electron system (2DES). We find that at nu<or=1/3 the 2DES is fully spin polarized. Increasing the filling factor results in a gradual depolarization, with a sharp minimum in the dichroism near nu=2/3. We find that in the range 0.5<or=nu<0.85 the 2DES remains partially polarized for the broad range of magnetic fields from 2.75 to 11 T. This is consistent with the presence of a mixture of polarized and depolarized regions.
我们展示了在0 < ν ≤ 1范围内，GaAs量子阱中分数量子霍尔 regime下的光学带间吸收测量结果。我们研究了单重态三重子吸收的机制，并表明其圆二色性可作为二维电子系统（2DES）基态自旋极化的探针。我们发现，在ν ≤ 1/3时，2DES完全自旋极化。增加填充因子会导致逐渐去极化，在ν = 2/3附近的二色性有一个急剧的最小值。我们发现，在0.5 ≤ ν < 0.85范围内，对于2.75至11 T的宽磁场范围，2DES保持部分极化。这与极化和去极化区域混合的存在是一致的。
