d0半导体纳米材料中磁性来源以及增强的物理机制研究

项目名称： d0半导体纳米材料中磁性来源以及增强的物理机制研究

项目编号： No.11204137

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学I

项目作者： 吴芳

作者单位： 南京林业大学

项目金额： 22万元

中文摘要： 具有室温磁性的半导体纳米材料，在电子器件和信息材料中有着广阔的应用前景。近年来,实验研究报道了在一些不包含任何磁性原子的半导体(d0半导体)纳米材料中存在室温磁序，但是其实验和应用的发展却被两个关键问题所阻碍：1)局域磁矩的来源；2）低浓度的局域磁矩如何形成宏观磁序？本项目拟采用密度泛函理论的方法，研究在d0半导体纳米材料中(表面、纳米线和纳米团簇)，阳离子缺陷和包含阳离子的缺陷团簇的形成能力，揭示形成局域磁矩的物理来源。通过对纳米材料中局域磁矩间的磁有些相互作用距离进行研究，阐述纳米尺度对局域磁矩间耦合能力的影响，揭示实验观察到的室温磁序的可能来源。此外，理论上探索在现有的实验制备条件下，一些不可避免的外界因素（外界应力）对半导体纳米材料中局域磁矩形成能力以及磁相互作用的影响，并总结其一般规律，预言实验可能增强磁性的途径，为进一步的实验研究提供一些理论依据和指导。

中文关键词： 半导体纳米材料；第一性原理计算；电子结构；磁性质；量子限制效应

英文摘要： Semiconductor nanomaterials with room-temperature magnetism have attracted broad interests, because of the great promise in the applications of the next electric and data storage devices. In the recent year, experimental groups have reported excited results that room-temperature magnetism can be observed in the semiconductor nanomaterials without any magnetic atoms (d0 semiconductors). However, two issues, which have blocked the development of its applications, are still not clearly explored: (1)what is the origin of the local magnetic moments? (2)How do the collective magnetic ordering formed by the local magnetic moments with low concentration? In this proposal, we will investigate these issues in d0 semiconductor nanomaterials using density functional theory calculations. Through studying the formation ability of cation vacancies and cation-contained vacancies cluster, we explore the possible origion of local magnetic moments.To reveal the origin of room-temperature magnetism, we will investigate the magnetic interaction between local magnetic moments in nanomaterials and find out the effect of quantum confinement. By comparing with the formation ability of local magnetic moments, we will explore the possible origin of collective magnetic ordering observed in experiments. Moreover, we will also study whether

英文关键词： Semiconductor nanomaterials；First-principles calculations；Electronic structures；Magnetic properties；Quantum confinement