Structural stability and magnetic-exchange coupling in Mn-doped monolayer/bilayer MoS2
Structural stability and magnetic-exchange coupling in Mn-doped monolayer/bilayer MoS2
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Mn掺杂单层/双层MoS2的结构稳定性和磁交换耦合
DOI：
10.1039/c7cp05988d
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发表时间：
2018-01-07
影响因子：
3.3
通讯作者：
Ma, Fei
中科院分区：
文献类型：
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作者：
Fang, Qinglong;Zhao, Xumei;Ma, Fei
铁磁性(FM)、二维(2D)过渡金属二卤化物(TMD)在现代电子学和自旋电子学中具有潜在的应用前景，过渡金属掺杂可以提高TMDs的磁性。本文采用第一性原理计算方法，系统地研究了掺锰单层/双层MoS_2的结构稳定性、电子态和磁性。在富S的条件下，MoS_2单层和双层MoS_2中Mo位的替位Mn掺杂都具有良好的能量优势，这是合成MoS_2纳米片的常见条件。在单层MoS2中，两个Mn掺杂参与了FM相互作用，并且两个Mn掺杂之间的磁耦合可以通过最近邻的S来调节。磁耦合可以归因于双层MoS2中具有MniMnMo、MniMnS和Mn-Mo-Mn-Mo组态的两个Mn掺杂之间的双交换、直接交换和超交换相互作用的竞争。我们的结果揭示了磁交换耦合的几何依赖性，表明掺锰单层/双层MoS_2在自旋电子器件中具有很大的潜力。
Ferromagnetic (FM) two-dimensional (2D) transition metal dichalcogenides (TMDs) have potential applications in modern electronics and spintronics and doping of TMDs with transition metals can enhance the magnetic characteristics. In this work, the structural stability, electronic states, and magnetic properties of Mn-doped monolayer/bilayer MoS2 are studied systematically by first-principles calculations. Substitutional Mn dopants at the Mo sites are energetically favorable in both monolayer and bilayer MoS2 under the S-rich condition which is common in the synthesis of MoS2 nanosheets. Two Mn dopants participate in the FM interaction in monolayer MoS2 and magnetic coupling of two Mn dopants via the double-exchange mechanism can be mediated by the nearest neighboring S. Magnetic coupling can be ascribed to the competition between the double-exchange, direct-exchange, and super-exchange interactions, which take place between two Mn dopants in bilayer MoS2 with the MniMnMo, MniMnS and Mn-Mo-Mn-Mo configurations. Our results reveal the geometrical dependence of magnetic-exchange coupling suggesting that Mn-doped monolayer/bilayer MoS2 has large potential in spintronic devices.