磁性半导体/磁性d波超导结中的自旋极化输运

Spin-polarized transport in ferromagnetic semiconductor/ferromagnetic d-wave superconductor tunnel junction

通过求解磁性d波超导中的能隙与磁交换能的自恰方程,利用推广的Blonder-Tinkham-Klapwijk理论研究磁性半导体/磁性d波超导结中自旋极化准粒子输运系数与微分电导.计算表明:1)磁性d波超导结中的磁交换能h0可导致零偏压电导峰与能隙电导峰劈裂,劈裂的宽度为2h0;2)磁性半导体中的磁交换能hFS可使零偏压电导峰劈裂的峰值变低.而由能隙电导峰劈裂的两个子峰,当两种磁性材料的磁化方向平行时,右边的峰值随着hFS的变大而变高,左边的峰值变低,当两磁性材料的磁化方向反平行时,随hFS变大右边的峰值变低,左边的峰值变高.

By solving a self-consistent equation for the d-wave superconducting gap and the magnetization, and applying an extended Blonder-Tinkham-Klapwijk approach, we study the spin-polarized quasiparticle transport coefficients and the differential conductance in ferromagnetic semiconductor/ferromagnetic d-wave superconductor junction. It is shown that （ 1 ） the exchange energy h0 in the ferromagnetic d-wave superconductor may make the zero-bias conductance peak and energy gap peak split into two peaks, and the energy difference between the two splitting peaks is equal to 2h0; （2） the exchange energy hFS in the ferromagnetic semiconductor can decrease the height of the two peaks resulting from splitting of the zero-bias conductance peak. For the splitting of the energy gap conductance peak, however, with hFS increased the left-hand peak is lowered and the righthand peak is raised in the parallel configuration, but the left-hand peak is raised and the right-hand peak is lowered in the antiparallel configuration.