拓樸絕緣體之微波元件研究

Abstract

本文主要探討拓樸絕緣體的微波實驗，材料主要是硒化鉍（bismuth selenide，Bi_2Se_3），文中提出與其他團隊研究不同的寬頻微波量測方法，目的在於研究微波寬頻頻譜下拓樸絕緣體的動態行為。本文亦包含有關微波實驗中儀器的設置，因實驗需求本實驗需改裝實驗樣品量測桿以符合低溫微波量測之需求，包含微波接頭設計、製作，微波導線裝設等。文中呈現拓樸絕緣體 Bi_2Se_3 薄膜的低溫電阻率量測，並探討微波實驗中，共平面波導對於 S 參數的影響，模擬共平面波導之集總電路（lumped circuit）模型。

The purpose of this dissertation was to investigate the behavior of topological insulator bismuth selenide,Bi_2Se_3 , at low temperature. The idea of microwave broadband measurement of topological insulators is proposed in this dissertation. The installation of our low temperature microwave instruments are mentioned, including the design of 2.9 mm connectors for the sample probe and the semi-rigid cables installation for the sample probe. The low temperature resistivity measurement is also presented. Last, the characteristic of the coplanar waveguide affects the results of our microwave measurements. The lumped circuit model of our coplanar waveguide pattern is discussed.