影响磁性pn结自旋极化输运特性的因素

The factors influencing spin-polarized transport in magnetic pn junction

利用漂移扩散理论研究了磁性pn结中自旋的输运特性.探讨了外加电压、平衡自旋极化率、外加自旋注入和自旋寿命对磁性pn结电流密度和电阻的影响,讨论了磁性pn结自旋伏特效应与pn结宽度的关系.发现平衡自旋极化率使得不同自旋方向电子具有不同的势垒高度从而能有效调制电流;而外加自旋注入则为磁性pn结提供了非平衡自旋极化电子从而达到对电流的调制作用,同时发现自旋伏特电流随准中性p区宽度减小而增大.

Spin-polarized transport in magnetic pn junction has been theoretically studied by using the drift-diffusive theory. The factors considered include bias voltage,equilibrium spin polarization,spin injection and spin life time,which could effectively affect the current density and resistance. The connection between spin-voltaic effect of the magnetic pn junction and thickness of the junction was also discussed. It is found that the equilibrium spin polarization makes the spin electrons with different orientations （up or down） have different barriers,which makes the current effectively modulated. However, the spin injection modulates the current by providing non-equilibrium spin electrons in the magnetic pn junction. It is also found that the spin-voltaic current is sensitive to quasi-neutral p-type region width.