以極化飛秒光譜研究(110)Y0.7Ca0.3Ba2Cu3O7-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Y1-xCaxBa2Cu3O7-δ 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(110) Y0.7Ca0.3Ba2Cu3O7-δ薄膜，並且利用同步輻射的x-ray繞射法証實其(110)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(110)YCBCO薄膜上觀察在ab-diagonal (or nodal direction)方向上，其光激發準粒子的弛緩動力行為隨著不同參雜，如： over-doped、optimally-doped 與 under-doped的變化。

Anisotropic dynamics of Y1-xCaxBa2Cu3O7-δ thin films probed by a polarized femtosecond pump-probe system were investigated in our laboratory. In this thesis, we have successfully prepared the well-textured (110)-oriented Y0.7Ca0.3Ba2Cu3O7-δ thin films by pulsed laser deposition (PLD), and the (110) purity of (110)YCBCO thin films, as revealed by x-ray diffraction in National Synchrotron Radiation Research Center, was better than 98%. In addition, by used the encapsulated bulk annealing method to manipulate the oxygen content of the (110)YCBCO films, we can systematically investigate the relaxation dynamics of photoexcited quasiparticles for the ab-diagonal (nodal direction) as a function of various hole doping, i.e. overdoped, optimally doped and underdoped regions in a single (110)YCBCO film.