Structures, mobilities, electronic and magnetic properties of point defects in silicene
Structures, mobilities, electronic and magnetic properties of point defects in silicene
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硅烯中点缺陷的结构、迁移率、电子和磁性
DOI：
10.1039/c3nr02826g
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发表时间：
2013-01-01
期刊：
影响因子：
6.7
通讯作者：
Zhao, Jijun
中科院分区：
文献类型：
--
作者：
Gao, Junfeng;Zhang, Junfeng;Zhao, Jijun
在硅烯单层的制造和加工中，结构缺陷几乎是不可避免的。通过从头计算，我们系统地研究了硅烯中典型点缺陷的结构、形成能、迁移行为和电子/磁性特性，包括 Stone-Wales (SW) 缺陷、单空位和双空位（SV 和 DV）以及吸附原子。我们发现SW可以通过热退火有效地恢复。 SV 的移动性比 DV 高得多，并且两个 SV 很可能合并为一个 DV 以降低能量。 SW和DV的存在可能会在硅烯中产生小间隙，而SV缺陷可能会将半金属硅烯转变为金属硅烯。吸附原子出乎意料地稳定，可以极大地影响硅烯的电子特性。特别是，硅烯片中的硅吸附原子作为自掺杂剂可以引起长程自旋极化以及显着的带隙，从而实现全硅磁性半导体。目前的理论结果为在实验中识别这些缺陷以及了解它们对硅烯物理性质的影响提供了有价值的见解。
In the fabrication and processing of silicene monolayers, structural defects are almost inevitable. Using ab initio calculations, we systemically investigated the structures, formation energies, migration behaviors and electronic/magnetic properties of typical point defects in silicene, including the Stone-Wales (SW) defect, single and double vacancies (SVs and DVs), and adatoms. We found that SW can be effectively recovered by thermal annealing. SVs have much higher mobility than DVs and two SVs are very likely to coalesce into one DV to lower the energy. Existence of SW and DVs may induce small gaps in silicene, while the SV defect may transform semimetallic silicene into metallic. Adatoms are unexpectedly stable and can affect the electronic properties of silicene dramatically. Especially, Si adatoms as self-dopants in silicene sheets can induce long-range spin polarization as well as a remarkable band gap, thus achieving an all-silicon magnetic semiconductor. The present theoretical results provide valuable insights into identification of these defects in experiments and understanding their effects on the physical properties of silicene.