高溫超導體中Zhang-Rice Band隨電洞摻雜變化之探討

Abstract

在本論文中將利用同步輻射中心極化光源進行O K-edge和Cu L-edge X光吸收光譜(XANES)實驗，樣品為脈衝雷射蒸鍍系統(PLD, Pulse Laser Deposition System)所製備的Y0.7Ca0.3Ba2Cu3Oy薄膜。本實驗探討Y0.7Ca0.3Ba2Cu3Oy薄膜的銅氧平面費米能階(Fermi level；EF)附近能帶之光譜權重(spectral weight)，量測在高載子(電洞)濃度區域下的樣品以分析其電洞之分佈，進而檢證D. C. Peets et al. (Phys. Rev. Lett. 103, 087402 (2009)) 中的實驗結果。

In this thesis, We measured the x-ray absorption spectroscopy (XAS) at O K- and Cu L-edges of Y0.7Ca0.3Ba2Cu3Oy thin films which were fabricated by pulse laser deposition technique. We study the spectral weights to discuss the distribution of holes in the heavily overdoped regime, where the upper Hubbard could disappear and the existence of the Zhang-Rice singlets is questioned. We compare the results to testify the trend proposed by D. C. Peets et al. (Phys. Rev. Lett. 103, 087402 (2009)).