矽基板上成長的砷化鎘薄膜之磁傳輸

Abstract

本論文主要探討在矽基板上成長的砷化鎘薄膜之磁傳輸行為。當外加垂直於平面的磁場時，線性正磁阻現象被觀察到，而當外加平行電流方向的磁場時，則會產生負磁阻行為，並且可以歸因於手性異常效應，藉此證實三維狄拉克半金屬在外加磁場時，會因為時間反演對稱性被破壞而轉變為具有外爾半金屬相。除此之外，在垂直和平行磁場中都可以觀察到弱侷域化效應，並根據相位相干長度的溫度依賴性，我們推測在系統中的量子擴散傳輸行為是由電子-電子交互作用所主導。

In this thesis, the magnetotransport behavior of a Cd3As2 film grown on Si substrate with a ZnTe buffer layer has been discussed. Positive linear magnetoresistance appears in the presence of the perpendicular magnetic field, and negative magnetoresistance under a parallel magnetic field has been observed, which is attributed to the chiral anomaly effect. The appearance of the chiral anomaly effect provides evidence of the realization of the Weyl semimetal phase in 3D Dirac semimetal caused by time-reversal symmetry breaking. Besides, the weak antilocalization effect can be observed in both perpendicular and parallel magnetic fields. Based on the temperature dependence of phase coherence length, we concluded that the electron-electron interaction dominates the quantum diffusive transport in the system.