以飛秒光譜研究(001)Y0.7Ca0.3Ba2Cu3O7-δ薄膜之超快動力學

Abstract

在本論文中，我們利用本實驗室自行發展的極化飛秒激發探測光譜系統技術，來研究（001）Y0.7Ca0.3Ba2Cu3O7-δ薄膜的超快動力學。此薄膜是利用脈衝雷射蒸鍍法製備，並且利用X-ray繞射儀、溫度-電阻四點量測方法來分析確認薄膜的晶體結構和傳輸特性。另外，藉由實驗室的控氧技術，改變不同的載子濃度，從過度摻雜到缺乏摻雜得到不同的臨界溫度，並且量測在不同溫度下，薄膜的瞬時反射率隨著溫度的變化，觀察釔鈣（0.3）鋇銅氧（001）軸向的弛緩行為。

In this thesis, a femtosecond spectroscopy pump-probe system has been used to study the ultrafast dynamics of (001) Y0.7Ca0.3Ba2Cu3O7-δ thin films. The Y0.7Ca0.3Ba2Cu3O7-δ thin films were prepared by pulsed laser deposition (PLD) and their characterizations were examined by x-ray diffraction and a four-probe measurement. The hole doping concentration of the sample was varied from over-doping to under-doping ranges by an oxygen control technique. The changes of transient- reflectivity ( ) were measured by a femtosecond pump-probe system. The relaxation dynamics of photoexcited quasiparticles and the average gap information in ab plane as a function of hole doping concentration were investigated systematically.