本课题将利用联合分子束外延生长系统（MBE）的自旋分辨的角分辨光电子能谱（SARPES）对存在拓扑相变的(Bi1-xInx)2Se3和Pb1-xSnxSe单晶/薄膜体系自旋极化精细电子态和拓扑量子相变机制进行研究。采用自主研制的世界上首台基于交换相互作用的多通道超高效率自旋分辨的角分辨光电子谱仪对该单晶/薄膜材料电子态进行全参量表征（能量，动量，自旋）。主要研究有两方面：1）细致测量一系列不同组分单晶材料电子态变化，研究能带反转和相变过程中体态/表面态电子自旋的变化，观察体系相变过程，研究拓扑相变机制；2）生长高质量的薄膜材料，研究薄膜层数和掺杂量对自旋轨道耦合强度及表面电子态自旋极化度的影响，寻找调控薄膜电子自旋的途径。该课题研究对人工调控材料电子自旋性质有着重要意义，将推动拓扑绝缘体在自旋电子器件领域的应用。

In this project we study of spin-polarized fine electronic states and topological quantum phase transitions mechanism in topological materials ((Bi1-xInx)2Se3, and Pb1-xSnxSe single crystals and films) using spin- and angle-resolved photoemission spectroscopy (SARPES) combined with molecular-beam-epitaxy (MBE) system. We will characterize energy, momentum, and spin of electrons in these materials by highly efficient multi-channels SARPES, which is based on exchange-scattering interactions and developed by ourselves. The detail electronic states of the different doping single crystals will be systematically measured to study spin properties on the bulk and surface states in the process of band inversions and phase transitions, and further to probe phase transition mechanisms. Additional，we will epitaxial grow high quality film samples to study the strength of spin-orbit coupling and the degree of spin polarizations of the surface electronic states upon the quantities of the samples layers and impurities, seeking to manipulate spin freedom in the film. The studies of fine spin-polarized electronic states and topological phase transitions mechanism are very important for artificial regulating spin properties in the materials and will promote the potential applications of topological insulators in spintronics.