Martinek J, Utsumi Y, Imamura H, Barnaś J, Maekawa S, König J, Schön G
Institut für Theoretische Festkörperphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany.
Phys Rev Lett. 2003 Sep 19;91(12):127203. doi: 10.1103/PhysRevLett.91.127203.
We study the Kondo effect in a quantum dot coupled to ferromagnetic leads and analyze its properties as a function of the spin polarization of the leads. Based on a scaling approach, we predict that for parallel alignment of the magnetizations in the leads the strong-coupling limit of the Kondo effect is reached at a finite value of the magnetic field. Using an equation of motion technique, we study nonlinear transport through the dot. For parallel alignment, the zero-bias anomaly may be split even in the absence of an external magnetic field. For antiparallel spin alignment and symmetric coupling, the peak is split only in the presence of a magnetic field, but shows a characteristic asymmetry in amplitude and position.
我们研究了与铁磁引线耦合的量子点中的近藤效应，并分析了其作为引线自旋极化函数的性质。基于标度方法，我们预测，对于引线中磁化的平行排列，在有限磁场值下可达到近藤效应的强耦合极限。利用运动方程技术，我们研究了通过量子点的非线性输运。对于平行排列，即使在没有外部磁场的情况下，零偏置异常也可能被分裂。对于反平行自旋排列和对称耦合，峰值仅在存在磁场时被分裂，但在幅度和位置上表现出特征不对称性。
