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arXiv 2206.15313cond-mat.mes-hall
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过渡金属二硫族化合物合金上石墨烯的邻近自旋轨道耦合

Proximity spin-orbit coupling in graphene on alloyed transition metal dichalcogenides

Zahra Khatibi, Stephen R. Power

摘要:

石墨烯和过渡金属二硫属化物(TMDC)堆叠异质结构中的邻近效应可以增强石墨烯中可忽略的固有自旋轨道耦合(SOC)。TMDC层的组成在确定石墨烯层中诱导的所得SOC的性质和强度中起关键作用。在这里,我们研究的邻近诱导SOC的TMDC层的演变是故意缺陷。用密度泛函理论模拟了不同组分($χ$)和缺陷分布的合金化${\rm G/W_χMo_{1-χ}Se_2}$异质结构.与连续和紧束缚模型的比较,可以澄清的金属原子合金化的本地和全球的签名。我们的研究结果表明,尽管个别缺陷的局部参数的一些戏剧性的扰动,低能量的自旋和电子的行为遵循一个简单的有效介质模型,它只依赖于TMDC层中的金属物种的组成比。此外,我们证明,这种合金系统的拓扑状态可以通过控制这个比例进行可行的调整。

英文摘要:

The negligible intrinsic spin-orbit coupling (SOC) in graphene can be enhanced by proximity effects in stacked heterostructures of graphene and transition metal dichalcogenides (TMDCs). The composition of the TMDC layer plays a key role in determining the nature and strength of the resultant SOC induced in the graphene layer. Here, we study the evolution of the proximity-induced SOC as the TMDC layer is deliberately defected. Alloyed ${\rm G/W_χMo_{1-χ}Se_2}$ heterostructures with diverse compositions ($χ$) and defect distributions are simulated using density functional theory. Comparison with continuum and tight-binding models allows both local and global signatures of the metal-atom alloying to be clarified. Our findings show that, despite some dramatic perturbation of local parameters for individual defects, the low-energy spin and electronic behaviour follow a simple effective medium model which depends only on the composition ratio of the metallic species in the TMDC layer. Furthermore, we demonstrate that the topological state of such alloyed systems can be feasibly tuned by controlling this ratio.

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