以極化飛秒光譜研究(100)Y0.9Ca0.1Ba2Cu3O7-δ薄膜之超快動力學

Abstract

本實驗室一直致力於使用飛秒極化光譜研究高溫超導體YCaxBaCO7 薄膜的各向異性超快動力學。在本論文中，我們成功地利用脈衝雷射鍍膜製備高品質(100) Y0.9Ca0.1Ba2Cu3O7-δ薄膜，並且利用同步輻射的x-ray繞射法証實其(100)軸向的純度百分率高達98%以上。搭配樣品控氧方法改變YCBCO薄膜的氧含量，我們可以有系統地從同一個(100)YCBCO薄膜上觀察在b軸方向上，其光激發準粒子的弛緩動力行為隨著不同摻雜，如： 過度摻雜、最佳摻雜與不足摻雜的變化。

Anisotropic dynamics of YCaxBaCuO7-δ thin films probed by a polarized femtosecond pump-probe system have been investigated continuously in our laboratory. In this thesis, we have successfully prepared the well-textured (100)-oriented Y0.9Ca0.1Ba2Cu3O7-δ thin films by pulsed laser deposition (PLD), and the (100) purity of (100)YCBCO thin films, as revealed by x-ray diffraction in National Synchrotron Radiation Research Center, was better than 98%. In addition, by using the encapsulated bulk annealing method to control the oxygen content of the (100)YCBCO films, we can systematically investigate the relaxation dynamics of photoexcited quasiparticles along the b-axis as a function of various hole doping, i.e. overdoped, optimally-doped and underdoped regions in a single (100)YCBCO film.