共振價鍵態對石墨烯自旋電子學的研究

Abstract

本論文以自旋電子學的角度研究石墨烯在自旋電子元件中應用的可能性。此論文探討關於氧化鋅與摻鈷氧化鋅產生磁性的原因，認為在氧化鋅結構中缺陷的產生會引發磁性，所以我們分別討論氧缺陷與鋅缺陷對氧化鋅磁性的影響。並提出磁性氧化鋅中因鋅缺陷存在共振價鍵態（RVB）並產生自旋液態有序（SLO）。將石墨烯沉積在摻鈷氧化鋅的表面上時石墨烯會因近鄰效應而感應出磁化耦合交互作用並具有RVB態，此時含有RVB態的石墨烯在接近化學能的線性能帶中表現出淨自旋極化，這時石墨烯將可以產生自旋電流而具有自旋電子元件應用的潛能。建構的理論模型包含鈷摻雜對於氧 化鋅影響與石墨烯沉積在摻鈷氧化鋅表面自旋特性的研究。

Investigate of the magnetic properties of graphene providing the potential in spintronic applications as well as the discussion of the zinc oxide (ZnO) inducing ferromagnetism will be reprsented in this thesis. Since the znic oxides possess some vacancies which produce ferromagnetism. we dicuss the effect of the oxygen vacancy (Ov) and the zinc vacancy (Znv) in the ferromagnetism induction, respectively. We also propose the spin-liquid order (SLO) produced from the resonating valence bond (RVB) states existing in the ferromagnetic zinc oxides and which will be transferred to graphene by inducing a magnetoc coupling as it is deposited on the surface of cobalt doped zinc oxide (CZO). In the resonating valence bond states involved graphene a net spin polarization will br observed in the linear bands with the chemical potential energy. The theoretical model is constructed to investigate the mechanics of ferromagnetism as well as the spin characteristics of CZO.