Computational quantum transport in mesoscopic electronic waveguides

高数值复杂性的介观系统中的量子输运导致输运性质的高可变性将被研究。具体来说，我们研究了外加磁场对复杂电子波导传输的影响。后者由具有可调谐光谱的量子点的有限阵列组成，通常是不同的。点的几何形状，引线的位置，特别是磁场的应用，无论是均匀的还是不均匀的，都会影响电子动力学，从而影响波导的输运性质。改变和优化阵列的几何形状，有限温度引起的热展宽，电流的非相干贡献和自旋相关输运是需要研究的相关方面。计算方案基于递归格林函数技术的二维并行化版本，允许处理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发展和改进是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，二维和三维的广泛应用将被执行，从而解决只有少数横向激发到全三维量子输运的情况。我们的目标是开发出一种设备，可以通过改变外场的振幅来广泛控制电子输运。

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.