Alternative Title第一原理計算による半導体中の最隣接遷移金属不純物対の磁気・化学相互作用に関する研究
Note (General)Magnetic and chemical interactions of the nearest neighbor transition metal impurity pairs in semiconductors have been studied over the past few decades in order to understand, and ultimately control magnetic properties of transition metal doped semiconductors in the search for novel magnetic materials. For the mechanisms of these pairwise interactions,several pictures based on conventional phenomenological models have been presented. However, these pictures can only partially capture trends in these pairwise interactions and have not even given a congruous view of these pairwise interactions for the very same materials. This thesis tackles the issues of the mechanisms of these pairwise interactionsbased on density functional theory calculations. Density functional theory calculations are among the most widelyused ab initio electronic structure approaches today, particularly in the condensed matter physics community. By using such calculations, one can obtain electronic structure as solution to the fundamental manyelectronion Hamiltonian instead of presupposing the preferred type of electronic interactions. Therefore, the calculations may allow us to identify the important factors for the mechanisms of these pairwise interactions that are omitted in the formulation of the conventional phenomenological models, and may unveil the true mechanisms underlying the observed different types of magnetic interactions. We first reveal that a peculiar ferromagnetic coupling of the Cr impurity pairs in AlN that cannot be interpreted by conventional magnetic models is mainly due to d-d interactions that are usually assumed to be negligible. Next, we reveal for what kind of materials d-d interactions become important in the description of pairwise magnetic and chemical interactions of the TM impurities in III-V semiconductors.
Collection (particular)国立国会図書館デジタルコレクション > デジタル化資料 > 博士論文
Date Accepted (W3CDTF)2016-08-04T09:59:51+09:00
Data Provider (Database)国立国会図書館 : 国立国会図書館デジタルコレクション