自旋與電荷在拓樸絕緣體中之轉換效應

Spin-to-charge Conversion in Topological Insulator

本文簡介了電荷流、極化電流與自旋流，自旋流產生和檢測之機制以及自旋電荷轉換等自旋電子學重要觀念，並介紹了一個新穎的材料：拓樸絕緣體。我們在拓樸絕緣體異質結構中在調整費米能階位置調控自旋電荷之轉換。通過自旋幫浦測量分析，揭示了自旋電荷轉換與拓樸絕緣體的費米能階高度的相依關係。結果顯示，當費米能接近狄拉克點時，自旋流可在最大程度上轉化為電荷流。我們的研究工作提供了一種新方法，可以通過控制拓樸絕緣體的費米能階來實現有效的自旋電荷轉換。而自旋電荷轉換對於自旋電子元件中的讀寫功能，以及對低能耗高速元件的研發都是非常重要的課題與關鍵技術。

This article introduces several important concepts in spintronics such as charge current, polarized current and spin current, the mechanism of spin current generation and detection, and spin-to-charge conversion. A novel material, topological insulator, is also introduced. In the heterostructures of topological insulator and magnetic materials, we adjust the Fermi level to tune the spin-to-charge conversion. Through spin pumping study, the dependence of spin-to-charge conversion on the Fermi level of topological insulators is revealed. The results show that when the Fermi energy approaches the Dirac point, a spin current can be transformed into a charge current to the greatest extent. Our research work provides a new method to achieve effective spin-to-charge conversion by controlling the Fermi level of topological insulators. Spin-to-charge conversion is a very important subject and key technology for the reading and writing functions of spintronic devices, as well as for the development of low-energy consumption and high-speed devices.