在本論文中，我們藉由第一原理自旋極化局域密度近似(LSDA)，並考慮強關聯哈伯參數U(LSDA+U)，研究掺雜的鈣鈦礦結構錳氧化物YMExMn1-xO3(ME = Co、Ni、Cu)的電子結構及磁性性質。首先，我們研究了哈伯參數U在六角晶體結構YMnO3磁有序所造成的效應。另一方面，在我們的電子態密度計算中顯示出在這三種掺雜的錳氧化合物(x=0.25)中均有Mn3+-Mn4+混合價數的現象。此外，在我們的計算中也發現到在YME0.25Mn0.75O3(ME= Co、Ni、Cu)中由各種掺雜元素引發不同的軌域有序。 In this thesis, we investigated the electronic structures and magnetic properties of doped perovskite magnanites, YMn1-xMExO3 (ME=Co, Ni, Cu), by means of density functional method within a spin-polarized local density approximation + Hubbard U (LSDA+U). First of all, the effect of parameter U on the magnetic ordering in hexagonal YMnO3 has been studied. Meanwhile, a mixed valent Mn3+-Mn4+ in all three moderated doped magnanites (x=0.25) has revealed from our calculated electronic density of states. Furthermore, different dopant-induced orbital orderings corresponding to various YME0.25Mn0.75O3 were found in our calculations.
