雙指閘元件的自旋共振量子傳輸

Abstract

本研究工作探討N型雙指閘 (DFG) 元件的共振量子傳輸。我們研究在強Rashba自旋軌道交互作用以及外加縱向磁場引發Zeeman效應的作用下，如何影響此DFG元件之共振傳輸特性。此DFG系統為具有高遷移率之準一維量子通道，而其寬度可用一對分離閘極加以控制。子帶結構的自旋簡併性將分離成拋物線狀的上自旋分支，以及具有子帶頂端的下自旋分支。我們以解析和數值驗證電導的尖峰結構為強Rashba-Zeeman耦合效應所產生的共振態 (RS)、似電洞束縛態 (HBS)、以及似電子準束縛態 (EQBS)。我們的研究工作可以提供處理量子資訊或是資料儲存類型的自旋元件之理論基礎，並作為設計原型的參考。

This work investigates the spin-resolved resonant quantum transport in an n-type double finger gate (DFG) device. We study how the strong Rashba spin-orbit interaction and an applied longitudinal magnetic field induced Zeeman effect influence the transport properties of the DFG device. The considered DFG system is a high mobility quantum channel and its width can be controlled by a pair of split-gate. The subband structure is split into a parabolic spin-up branch and a spin-down branch involving a subband top. We have demonstrated analytically and numerically that various peak structures in conductance are corresponding to resonant state, hole-like bound state, and electron-like quasi-bound state features due to strong Rashba-Zeeman coupling effect. We believe that our theoretical work could provide a guideline to design a prototype of a RZ effect based spintronic device for quantum information storage and transfers.