能譜影像研究鐵基高溫超導體的電子結構

Spectroscopic Imaging on the Electronic Structures of Iron-based High Temperature Superconductors

莊天明

《真空科技》 27卷2期 (2014/06) Pp. 71-77

摘要

我們運用掃描穿隧顯微鏡（Scanning Tunneling Microscope, STM）在兩個鐵基高溫超導體系統上進行能譜影像研究，在Ca（Fe_(0.97)Co_(0.03)）_2As_2母體相（parent phase）中，我們觀察到向列型（nematic）電子結構，但是我們的結果顯示比原先理論預測更複雜的對稱性破壞。而在LiFeAs超導態中，我們利用準粒子干涉（quasiparticle scattering interference, QPI）技術，測量到α_2和γ能帶上超導能隙的異向性，這個量測結果對於發展定量的高溫超導理論極為關鍵。

並列摘要

We use scanning tunneling microscope (STM) to carry out the spectroscopic imaging studies on two family members of iron-based high temperature superconductors. In the parent phase of Ca (Fe_(0.97)Co_(0.03))_2As_2, we discover the nematic electronic structure. From our observation, the electronic nematicity appears to be more complex than originally expected. In the superconducting LiFeAs, we introduce the intraband quasiparticle scattering interference technique to determine the anisotropy of superconducting energy gaps in α_2 and γ bands in momentum space. These measurements are of great importance for advance quantitative theoretical analysis of the Cooper pairing mechanism in iron-based superconductors.