Niels Bohr International Academy, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark.
Phys Rev Lett. 2013 Aug 9;111(6):066802. doi: 10.1103/PhysRevLett.111.066802. Epub 2013 Aug 6.
Based on the spin-blockade model for organic magnetoresistance, we present an analytic expression for the polaron-bipolaron transition rate, taking into account the effective nuclear fields on the two sites. We reveal the physics behind the qualitatively different magnetoconductance line shapes observed in experiment, as well as the ultrasmall magnetic field effect (USFE). Since our findings agree in detail with recent experiments, they also indirectly provide support for the spin-blockade interpretation of organic magnetoresistance. In addition, we predict the existence of a similar USFE in semiconductor double quantum dots tuned to the spin-blockade regime.
基于有机磁电阻的自旋阻塞模型，我们提出了一个考虑两个位置上的有效核场的极化子-双极化子跃迁率的解析表达式。我们揭示了实验中观察到的定性不同的磁导率线形状以及超小磁场效应（USFE）背后的物理机制。由于我们的发现与最近的实验结果非常吻合，因此它们也间接地支持了有机磁电阻的自旋阻塞解释。此外，我们还预测了在调谐到自旋阻塞区域的半导体双量子点中存在类似的 USFE。
