Impurity clustering and ferromagnetic interactions that are not carrier induced in dilute magnetic semiconductors:: The case of Cu2OCo
Impurity clustering and ferromagnetic interactions that are not carrier induced in dilute magnetic semiconductors:: The case of Cu2OCo
复制标题
DOI：
10.1103/physrevlett.99.167203
复制
发表时间：
2007-10-19
影响因子：
8.6
通讯作者：
Zunger, Alex
中科院分区：
文献类型：
--
作者：
Raebiger, Hannes;Lany, Stephan;Zunger, Alex
目前稀磁半导体中铁磁性的模型，如“p-d交换”或“双交换”，依赖于部分填充的带隙状态的存在。我们指出了一种不需要部分填充态的新机制，在这种机制中，当两个过渡金属杂质形成紧密对时，铁磁耦合是由于占据先前未占据的能级而产生的。我们从第一性原理计算中发现，这一机制解释了Cu2O中Co杂质之间强烈的铁磁耦合，同时也导致了Co团簇的产生。
Current models for ferromagnetism in diluted magnetic semiconductors, such as "p-d exchange" or "double-exchange", rely on the presence of partially filled gap states. We point out a new mechanism, not requiring partially filled states, in which ferromagnetic coupling arises from the occupation of previously unoccupied levels when two transition metal impurities form a close pair. We find from first-principles calculations that this mechanism explains strong ferromagnetic coupling between Co impurities in Cu2O, and at the same time gives rise to Co clustering.