Anisotropic nuclear-spin diffusion in double quantum wells
Anisotropic nuclear-spin diffusion in double quantum wells
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双量子阱中的各向异性核自旋扩散
DOI：
10.1103/physrevb.91.115318
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发表时间：
2015
影响因子：
3.7
通讯作者：
and Y. Hirayama
中科院分区：
文献类型：
--
作者：
T. Hatano;W. Kume;S. Watanabe;K. Akiba;K. Nagase;and Y. Hirayama
在朗道能级填充因子自旋相变(SPT)下，用动态核极化(DNP)研究了双量子阱(QWS)中的核自旋扩散。在两个量子波中的一个量子波(“极化量子波”)的DNP过程中，纵向电阻通过大的外加电流而增加，并在DNP终止后开始减小。另一方面，在极化QW的DNP终止后，另一个QW(检测QW)的纵向电阻持续增加约2小时。因此，得出结论：核自旋从极化量子波扩散到探测量子波。极化量子波纵向电阻的时间演化主要由面内的核自旋扩散来解释。与之相反，探测量子阱表现出在垂直方向上穿过AlGaAs势垒的核扩散要慢得多。
Nuclear spin diffusion in double quantum wells (QWs) is examined by using dynamic nuclear polarization (DNP) at a Landau level filling factorspin phase transition (SPT). The longitudinal resistance increases during the DNP of one of the two QW (the “polarization QW”) by means of a large applied current and starts to decrease just after the termination of the DNP. On the other hand, the longitudinal resistance of the other QW (the “detection QW”) continuously increases for approximately 2 h after the termination of the DNP of the polarization QW. It is therefore concluded that the nuclear spins diffuse from the polarization QW to the detection QW. The time evolution of the longitudinal resistance of the polarization QW is explained mainly by the nuclear spin diffusion in the in-plane direction. In contrast, that of the detection QW manifests much slower nuclear diffusion in the perpendicular direction through the AlGaAs barrier.