鉛金合金係由金與鉛兩種大原子序的原子構成，其能帶結構可以看到很強的Rashba effect。為了瞭解它電性傳輸上的表現，首先我們在超高真空中生長鉛金合金薄膜。完成鉛金合金薄膜之後，將樣品自超高真空腔體取出並以光刻法將樣品加工成Hall-bar機制。接著加上與樣品表面平行的外磁場並且在低溫下進行磁阻的測量。從實驗的結果中我們發現當溫度低於鉛的超導臨界溫度6K時，橫方向上的電壓將因自旋極化並具有電荷性電流而激增。此外，我們電壓在弱磁場0.2 Tesla至3.6 Tesla範圍中，發現電壓隨磁場鎮有震盪行為，並且電壓與電流具有非歐姆定律的關係。。
我們可以透過Rashba effect造成自旋霍爾效應或者反常霍爾效應來理解自旋極化電荷性電流的出現。此種自旋極化電荷性電流與鉛薄膜的超導行為密切相關，因為傳導電流會集中於鉛薄膜而導致電子在頂端具有很強Rashba effect的鉛金合金而被散射的機率大增。此種強自旋軌道耦合作用除了造成自旋極化電流的擴散之外，還極有可能透過Rashba作用造成超導態的轉變，形成time-resolved對稱性破壞。當溫度在超導臨界溫度之上時，自旋極化電荷性電流很小，因此比較遵守歐姆定律。最後，我們可以按照電子的自旋磁矩在外磁場下的進動現象來了解電壓隨弱磁場的震盪行為。

Binary surface alloy made of heavy elements, Pb and Au, has exhibited strong Rashba effect in its band structure. To investigate its corresponding performance in electric transport, we first grew such a PbAu-alloy thin film, composed of the Pb film with PbAu alloy layer on the top, in the UHV chamber. After the sample of PbAu-alloy film was made, we took the sample out of UHV chamber and fabricate it into a Hall-bar device via lithography for low-temperature magneto-resistance measurement with the applied magnetic field parallel to the sample surface. Based on the experimental result, we could find that once the temperature dropped below transition temperature. ~ 6 K, of Pb, the spin-polarized charge current appeared in the transverse direction causing the observed abrupt increase of the voltage. Furthermore, we also observed that the oscillation of voltage as a function of applied magnetic field in the weak limits from 0.2 Tesla to 3.6 Tesla and the non-ohmic behavior in terms of the I-V relation.
One can realize the appearance of spin-polarized charge current by considering the influence from Rashba effect, leading to spin Hall or anomalous Hall effect. Such spin -polarized charge current is closely related to superconductivity of Pb thin films; when the temperature goes below the transition temperature, the transport currents would concentrate on the Pb film so as to increase the probability of scattering to top PbAu alloy layer that has giant Rashba effect. Such strong spin-orbital interaction would not just lead to the diffusion of spin-polarized current in transverse direction but very likely breaking time-resolved symmetry via the change of superconducting state under Rashba interaction. When the temperature goes above transition temperature, spin polarized charge current is small, so the behavior becomes more Ohmic. Finally, the measured oscillation of voltage under the weak magnetic field could be realized by considering spin-magnetic moment of electrons in the spin-polarized charged currents exposed to the external magnetic field resulting in precession of spin magnetic moment.

摘要 I
Abstract III
目錄 V
圖目錄 VII
第一章緒論 1
第二章基礎理論 3
2.1晶格與晶面 3
2.2 倒晶格 5
2.3能帶結構 7
2.4光電子能譜 8
2.5 自旋軌道耦合 11
2.6Rashba effect 13
2.7自旋霍爾效應 17
2.8鉛金合金 22
第三章儀器原理介紹 26
3.1超高真空 26
3.2低能量電子繞射儀 28
3.3紫外光源 30
3.4角解析光電子能譜儀 31
3.5免液氦低溫強磁場系統 34
第四章樣品製備與製程 38
4.1鉛金合金樣品製備 38
4.2光刻 44
第五章實驗結果與討論 48
5.0前言 48
5.1電路於零磁場下的電壓與電流關係 51
5.2 平行外磁場下的電壓與磁場關係 53
5.3結果討論 57
第六章總結 69
第七章參考文獻 70

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