Basic Research of a Spin Transistor Based on the Quantum Transport in an Inhomogeneous Magnetic Field

这个项目是针对由复合半导体组成的复合半导体和纳米结构组成的带结构和量子载波传输的分析的。我们已经获得了迄今为止的结果：·对半导体纳米结构的波段结构的分析，如量子井和量子电线将自旋轨道相互作用纳入这个分析，我们已经将常规抛物线波段近似纳入量子纳米结构的预测和设计光学性能纳入其中，不再适用于量子纳米结构的预测和设计光学性能。我们还发现了一个外部电场，显著地影响了这种纳米结构的波段结构（星形效应），其中可以通过将其精确地模拟到计算出多波段效应质量理论和旋转轨道耦合。对载体在纳米结构中的量子传输的分析我们描述了一种方法来计算纳米结构中的量子传输的计算。在这个方法中，我们使用现场运算符的晶格-维格纳-韦尔公式来计算量子力学分布函数（维格纳-韦尔函数），而在多带效应质量理论中，我们使用该公式。与载体密度和粒子流动密度相比，这种物理量可以比常规方法更好地计算出分布功能。该公式被应用于分析量子孔传输在一个双屏障共振隧道二极管中。作为一个结果，当前的电压特征显示了具有一定意义的波段混合的自然光洞和重洞。这一理论可能适用于分析量子光学设备中的量子传输，例如量子良好的激光器和光电调制器，其中的波段混合效应发挥了一个重要的作用。

This project has been aimint at the analysis of the band structures and the quantum carrier transport in both diluted magnetic semiconductors and nano structures composed of compound semiconductors. We have obtained the following results so far :・Analysis of the band structures of semiconductor nano structures such as quantum wells and quantum wires taking the spin-orbit interaction into accountFrom this analysis, we have concluded the conventional parabolic band approximation is no longer appropriate to predict and design optical properties of quantum nano structures. We have also found an external electric field significantly affects the band structures of such nano structures (Stark effect) which can be precisely simulated by taking into account both the multi-band effective mass theory and the the spin-orbit coupling.・Analysis of the quantum transport of carriers in nano structuresWe describe a method for calculating quantum transport of carriers in nano structures. In this method, we use the lattice-Wigner Weyl formalism of the field operators to deduce the quantum mechanical distribution function (Wigner-Weyl function) in which multiband-effective-mass theory is taken into account. The physical quantities such as carrier densities and particle flow densities can be more readily computed from the distribution function than conventional methods. The formulation is applied to analyze quantum hole transport in a double barrier resonant tunneling diode. As a result, the current-voltage characteristics show considerable band-mixing nature of the light hole and the heavy hole. This theory may be applicable to analyze quantum transport of carriers in quantum optical devices such as quantum-well lasers and electro-optical modulators where the band-mixing effect plays an important role.