Double spin resonance in a spatially periodic magnetic field with zero average
Double spin resonance in a spatially periodic magnetic field with zero average
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DOI：
10.1209/0295-5075/94/28001
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发表时间：
2011-04
期刊：
影响因子：
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通讯作者：
A. Nogaret;F. Nasirpouri;J. Portal;H. Beere;David A. Ritchie;A. Hindmarch;C. Marrows
中科院分区：
文献类型：
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作者：
A. Nogaret;F. Nasirpouri;J. Portal;H. Beere;David A. Ritchie;A. Hindmarch;C. Marrows
本文报道了在零平均周期磁场调制的二维电子系统中自旋共振的电检测。在微波照射下，施加在平面上的大磁场可以提高自旋简并度。没有磁调制，电阻不检测自旋共振。然而，随着磁调制的开启，一个吸收峰出现了。峰值的频率和温度依赖性产生了GaAs/AlGaAs量子阱中电子的塞曼能量。我们将吸收峰解释为两个自旋翻转跃迁之间竞争的结果：一个是由在正负磁场域边界振荡的蛇轨道激活的，另一个是由微波激活的。当两个跃迁同时发生共振时，系统形成一个黑暗状态，阻止自旋翻转并冻结蛇形轨道通道。蛇轨道通道的相干抑制解释了观测到的共振的实验特征。
We report on the electrical detection of spin resonance in a two-dimensional electron system modulated by a periodic magnetic field with zero average. Spin degeneracy is lifted by a large magnetic field applied in the plane while the system is irradiated with microwaves. Without magnetic modulation, the resistance does not detect spin resonance. However an absorption peak develops as the magnetic modulation is switched on. The frequency and temperature dependences of the peak yield the Zeeman energy of electrons in the GaAs/AlGaAs quantum well. We interpret the absorption peak as the result of competition between two spin-flip transitions: one activated by snake orbits oscillating at the boundary between positive and negative magnetic field domains, the other by microwaves. When both transitions are simultaneously resonant, the system forms a dark state which blocks spin flips and freezes snake orbit channelling. The coherent suppression of snake orbit channelling explains the experimental features of the observed resonance.