Computational quantum transport in mesoscopic electronic waveguides

将研究介观系统中的量子输运，介观系统的数值复杂性导致输运性质的高度可变性。具体来说，我们研究了复杂的电子波导传输的外部磁场的影响。后者由具有可调光谱的通常不同的量子点的有限阵列形成。点的几何形状、引线的定位以及特别是均匀或不均匀的磁场的施加影响电子动力学，从而影响波导的传输特性。变化和优化阵列的几何形状，热加宽由于有限的温度，不相干的贡献的电流和自旋相关的运输是相关的方面进行研究。计算方案是基于一个二维并行版本的递归绿色的功能技术，允许治疗高度复杂的结构和几何形状。计算算法在效率和适用范围方面的进一步开发和改进代表了该项目的重要组成部分，特别是扩展到三维设置。在上述意义上的二维和三维中的广泛应用将被执行，从而解决只有几个横向激发到完全三维量子输运的情况。我们的目标是开发设备，允许一个广泛的控制电子传输与变化幅度的外部场。

Quantum transport in mesoscopic systems of high numerical complexity resulting in a high variability of transport properties will be investigated. Specifically we study the impact of external magnetic fields on the transmission of complex electron waveguides. The latter are formed by finite arrays of, in general different, quantum dots possessing tunable spectra. The geometry of the dots, the positioning of the leads and hi particular the application of magnetic fields, either homogeneous or inhomogeneous, influence the electron dynamics and consequently the transport properties of the guide. Varying and optimizing the geometry of the arrays, thermal broadening due to finite temperature, incoherent contributions to the currents and spin-dependent transport are relevant aspects to be studied. The computational scheme is based on a two dimensional parallelized version of the recursive Green s function technique, allowing to treat highly complex structures and geometries. Further development and improvement of the computational algorithm with respect to efficiency, and range of applicability represents a significant part of the project including in particular the extension to three dimensional setups. Extensive applications in two and three dimensions in the above sense are to be performed thereby addressing situations of only a few transversal excitations to full three dimensional quantum transport. The goal is to develop devices that allow for an extensive control of the electronic transport with varying amplitude of the external field.