奈米接面系統與摻雜系統磁性原子之 萬尼爾函數

Abstract

在這篇論文中，我們結合了以密度泛函理論為架構的第一原理計算軟體 Quantum espresso 與 Maximally localized Wannier function的計算軟體Wannier90，利用其計算了鈷原子於孤立原子系統、銅鈷銅奈米接面系統與鈷原子摻雜銅塊材系統這三種系統。藉由觀察鈷原子在不同系統中的變化，我們發現其磁性、PDOS與Maximally Localized Wannier function皆與磁性原子和其鄰近原子間的對稱關係有顯著的關聯，我們也發現鄰近原子與磁性之間的距離會影響磁性原子上各Wannier function的spread，且在打開自旋極化後其spread與energy 也會出現自旋分裂的現象。

In this thesis, we have applied the maximally localized Wannier function approach[Wannier90] to a density function theory based first principle code[Quantum espresso]. In order to understand the behavior of magnetic atom in different environment, we calculate three different systems which are isolated atom system, CuCoCu nanojunction system and Co doped in Cu bulk system. We found that magnetic properties, PDOS and Maximally localized Wannier functions will be varied depends on the symmetry between the magnetic d orbital and nearest atoms around it. We also found spreads of MLWF will be changed depending on distance between MLWF and nearest atoms around it and spreads also depends on spin if it is a spin polarized case.