Andriotis Antonis N, Menon Madhu
Institute of Electronic Structure and Laser, FORTH, PO Box 1527, 71110 Heraklio, Crete, Greece.
J Phys Condens Matter. 2018 Sep 26;30(38):385703. doi: 10.1088/1361-648X/aada9d. Epub 2018 Aug 16.
Our recent works have revealed that the magnetic coupling among the magnetic codopants in diluted magnetic semiconductors and doped transition metal oxides has a strong local feature. This was attributed to successive spin polarizations induced by the codopants to their neighboring anion ligands. In the present work, we analyze and refine the successive spin polarization based magnetic coupling using results of ab initio calculations and assign the magnetic coupling among the magnetic codopants to a combination of superexchange and double-exchange interactions. In particular, it is shown that antiferromagnetic successive superexchange interactions can lead to a ferromagnetic coupling between two magnetic dopants mediated by a suitable codopant with the latter forming a ferromagnetic double exchange coupling with its first nearest neighbor anions which couple it with the magnetic cations. This is exemplified by ab initio results for the magnetic coupling of two Co-dopants in the presence of a mediated Cu codopant in the environment of various hosts, namely ZnO, GaN, GaP, TiO, CdS and SnO. Additional results for other codopant pairs in various hosts are also presented.
我们最近的研究表明，稀磁半导体和掺杂过渡金属氧化物中磁性共掺杂剂之间的磁耦合具有很强的局域特性。这归因于共掺杂剂对其相邻阴离子配体诱导的连续自旋极化。在本工作中，我们使用从头算计算结果分析并完善了基于连续自旋极化的磁耦合，并将磁性共掺杂剂之间的磁耦合归因于超交换和双交换相互作用的组合。特别地，结果表明反铁磁连续超交换相互作用可导致由合适的共掺杂剂介导的两个磁性掺杂剂之间的铁磁耦合，后者与其第一近邻阴离子形成铁磁双交换耦合，从而将其与磁性阳离子耦合。这通过在各种主体（即ZnO、GaN、GaP、TiO、CdS和SnO）环境中存在介导的Cu共掺杂剂时两个Co掺杂剂的磁耦合的从头算结果得到例证。还给出了各种主体中其他共掺杂剂对的额外结果。
