Birefringent Spin Polarized Electron Optics in Ballistic Nano-Devices

Rashba自旋轨道相互作用是在不使用外部磁场或磁性材料的情况下在低维电子半导体系统中产生和操纵自旋极化的最有前途的效应之一。自1990年Datta和Das提出自旋场效应晶体管以来，许多理论观点已经发表。在这个项目中，我们将从理论和实验上探讨弹道二维电子和空穴系统中自旋电子光学的概念。碲化汞纳米结构，表现出强烈的Rashba型自旋轨道相互作用，是我们研究的基础。量子点接触用于弹道电子注入和检测，而自旋极化载流子的传播方向由栅极可控Rashba自旋轨道耦合强度来操纵。潜在的效应是光学活性偏振材料的双折射性质的电子模拟。理论上，电子束的传输和操纵由所谓的Landauer-Büttiker-Keldysh形式主义描述。我们将寻找电子束极化的效率和新颖的自旋干涉效应，可以从碲化汞纳米结构的复杂能带结构出现。

Rashba spin-orbit interaction is one of the most promising effects for the creation and manipulation of spin polarizations in low-dimensional electronic semiconductor systems without using external magnetic fields or magnetic materials. Since the introduction of the spin field-effect transistor by Datta and Das in 1990 many theoretical ideas have been published. In this project we explore, theoretically and experimentally, the concepts of spin electron optics in ballistic two-dimensional electron and hole systems. HgTe nanostructures, which exhibit a strong Rashba-type spin-orbit interaction, are the basis for our studies. Quantum point contacts are used for ballistic electron injection and detection while the propagation direction of spin polarized carriers is manipulated by the gate controllable Rashba spin-orbit coupling strength. The underlying effect is the electronic analogue of the birefringence properties of optically active polarizing materials. Theoretically, the electron beam propagation and manipulation is described by the so called Landauer-Büttiker-Keldysh formalism. We will look for the efficiency of electron-beam polarization and novel spin-interference effects which can emerge from the complex band structure of HgTe nanostructures.