A first-principles study on magnetic properties of the intrinsic defects in wurtzite ZnO.
A first-principles study on magnetic properties of the intrinsic defects in wurtzite ZnO.
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DOI：
10.1063/1.5063953
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发表时间：
2019-03
期刊：
影响因子：
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通讯作者：
Q. Lin;G. Li;N. Xu;H. Liu;D. E;C. L. Wang
中科院分区：
文献类型：
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作者：
Q. Lin;G. Li;N. Xu;H. Liu;D. E;C. L. Wang
由于氧化锌基稀磁半导体(DMS)的磁性起源仍存在争议，本文对具有点缺陷和复杂本征缺陷的纤锌矿结构DMS的磁性、结构和电学性质进行了详细的研究。来自中性氧空位(VO)的两个外层电子占据A1轨道，使感应磁矩为零，而含有3个VO的团簇产生的磁矩为∼1μB。含锌空位的体系的磁矩为1.6 5μB。当在各自的超晶胞中产生两个相对距离不同的中性VZN时，不同的VZn位引入的缺陷态的最高电子占据轨道与价带最大值之间的不等电平导致了不同的磁矩。中性O占据八面体位置的体系产生2μB的磁矩，而锌间隙缺陷和反位缺陷不会引起自旋极化。当空位相邻时，具有VO和VZn复合缺陷的系统是有磁性的，但仍然不会引起补偿效应。氧间隙缺陷是不稳定的，VZn容易转变为复杂缺陷。我们认为，VO团簇和VZn复合缺陷可能是未掺杂氧化锌铁磁性的根源。
Since the origin of magnetism in ZnO-based diluted magnetic semiconductors (DMSs) is still controversial, in this work, we presented a detailed study on the magnetic, structural, and electronic properties of wurtzite ZnO-based DMS systems with point and complex intrinsic defects. Two outer electrons from neutral oxygen vacancy (VO) occupy the a1 orbital, making the inducted magnetic moment to be zero, while a cluster including three VOs leads to a magnetic moment of ∼1 μB. The magnetic moment of the system with a Zn vacancy (VZn) is 1.65 μB. When two neutral VZns in different relative distances were created in respective supercells, the systems showed different magnetic moments induced by the unequal level between the highest electron occupied orbital of the defect state introduced by different VZn sites and the valence band maximum. The system of a neutral O occupying an octahedral site gives rise to a magnetic moment of 2 μB, while zinc interstitial and antisite defects do not cause spin polarization. The system with a complex defect of VO and VZn is magnetic when those vacancies are adjacent but still do not cause the compensation effect. The oxygen interstitial defect is unstable, and VZn easily turns into the complex defect. We suggest that VO clusters and VZn complex defects could likely be the origin of ferromagnetism in undoped ZnO.