Graduate School of Science, Chiba University, Chiba-shi, Chiba 263-8522, Japan.
Phys Rev Lett. 2010 Sep 17;105(12):126802. doi: 10.1103/PhysRevLett.105.126802. Epub 2010 Sep 15.
Spin relaxation of two-dimensional electrons in a GaAs/AlGaAs quantum well was studied by time-resolved Kerr rotation measurements using a two-color pump and probe technique. In quantum Hall ferromagnets, the spin-wave relaxation is strongly influenced by the photogenerated Skyrmion and anti-Skyrmion pairs. By tuning the pump and probe lights to the lowest optical transition, an intrinsic filling factor dependence of spin relaxation is obtained without photogeneration of Skyrmions. The relaxation time of the spin wave presents a sharp peak at odd filling factors, accompanied by dips on both sides of it. The peculiar filling factor dependence of the spin-wave relaxation around quantum Hall ferromagnets can be explained by the interaction between the spin wave and Skyrmion. Observation of a similar feature around ν=1, 3, and 5 may suggest the existence of Skyrmions around higher odd filling factors.
通过使用双色泵浦和探测技术的时间分辨克尔旋转测量，研究了 GaAs/AlGaAs 量子阱中二维电子的自旋弛豫。在量子霍尔铁磁体中，自旋波弛豫受到光生 Skyrmion 和反 Skyrmion 对的强烈影响。通过将泵浦光和探测光调谐到最低光学跃迁，在没有光生 Skyrmion 的情况下获得了自旋弛豫的固有填充因子依赖性。自旋波的弛豫时间在奇数填充因子下呈现出尖锐的峰值，其两侧有下降。在量子霍尔铁磁体周围，自旋波弛豫的特殊填充因子依赖性可以通过自旋波和 Skyrmion 之间的相互作用来解释。在 ν=1、3 和 5 周围观察到类似的特征可能表明在更高的奇数填充因子周围存在 Skyrmion。
